Bill Connelly ESPN Staff Writer 16 Minute Read

Have you made some proper halftime adjustments? Are you ready to roll? We commemorated the first half of college football's regular season earlier this week, and now it's time to go out for the second half!

To start, let's talk about the national title race. There are 13 primary title contenders at this point: nine unbeaten power-conference teams, plus four one-loss programs with at least a 1% chance at the ring, per the Football Power Index (FPI). Let's walk through the primary weaknesses each team has to overcome -- the "ifs" it takes to make each team a lead contender for the College Football Playoff -- to see what it tells us about how the race could play out.

Justin Fields' comfort in the pocket could become an issue. AP Photo/Jay LaPrete

1 If

Ohio State (6-0)

SP+ ranking: 1

FPI ranking: 2

FPI national title odds: 22.4%

If ... Justin Fields stays upright more.

The Buckeyes have beaten opponents by an average of 49-9, and three vanquished foes rank 36th or better in SP+. They are sixth in offensive SP+ and fourth on defense; they've fully re-weaponized after last season's team struggled with big plays on defense and ran the ball worse than Ohio State was used to.

There's one blind spot, however, that the Buckeyes would do well to fix before facing excellent defenses such as Northwestern's, Wisconsin's, Penn State's and Michigan's in the coming weeks.

Fields has been incredible this season, completing 70% of his passes with an 18-1 TD-to-INT ratio and rushing for 350 non-sack yards as well. But he does get a little too comfortable in the pocket sometimes.

Ohio State ranks just 93rd in sack rate allowed -- 94th on standard downs (first downs, second-and-7 or less, third- or fourth-and-4 or less), 91st on passing downs (second-and-8 or more, third- or fourth-and-5 or more), and 120th on blitz downs (second-and-20 or more, third-and-5 or more). Negative plays could pile up in a tight game against an elite team.

2 Ifs

Alabama (6-0)

SP+ ranking: 2

FPI ranking: 1

FPI national title odds: 32.2%

If ... the run defense comes around.

A run of fall camp injuries meant Alabama headed into 2019 with maybe the youngest front seven Nick Saban had ever fielded. This has had predictable effects. The Crimson Tide rank 26th in rushing success rate allowed (percentage of plays gaining 50% of necessary yardage on first down, 70% on second and 100% on third or fourth), 40th in opportunity rate allowed (percentage of carries gaining at least 4 yards) and 107th in stuff rate (run stops at or behind the line).

Things could be trending in the right direction -- Texas A&M running backs certainly didn't find much room last weekend -- but it must trend in the right direction for the Tide to avoid a stumble.

If ... third-and-medium becomes their friend.

Youth could also be contributing to some missteps on what you might call third-and-manageable. While the Tide defense ranks first in third-and-long (7 yards to go or more) success rate, it is an awful 102nd on third-and-medium (2 to 6 yards to go). Meanwhile, the offense ranks only 58th itself. That's not normal for Bama and must improve.

Clemson (6-0)

SP+ ranking: 8

FPI ranking: 3

FPI national title odds: 15.9%

If ... Trevor Lawrence comes around.

Much has been made of Lawrence's early-season struggles. It's hard not to assume things will end up all right in this regard, but a sophomore slump remains the biggest issue for the defending champs until rectified.

Clemson ranks just 59th in completion rate and 93rd in passing marginal efficiency (success rate that is adjusted for down, distance, and field position); the Tigers are 69th in third-and-medium success rate and 83rd on third-and-long. Even during their romp over Florida State, Lawrence averaged a merely decent 6.8 yards per pass attempt with a pick. It's an issue until it isn't.

If ... the Tigers tighten up in the red zone.

All told, Clemson shouldn't have nearly lost to North Carolina back on Sept. 28. The Tigers won the yardage battle, enjoyed a success rate margin of plus-9% (44% to 35%) and created more scoring opportunities (first downs inside the opponent's 40). But the Tar Heels scored touchdowns on all three trips, while Clemson faltered once. That was part of a trend -- the offense ranks 35th in points per scoring opportunity, and the defense ranks 48th. This isn't awful, but it isn't elite either.

LSU (6-0)

SP+ ranking: 5

FPI ranking: 4

FPI national title odds: 7.2%

If ... the front seven disrupts more.

LSU's offense has surpassed even the most optimistic of expectations this season, but there's a reason why the Tigers are still only fifth in SP+.

From 2002 to '18, only one LSU defense ranked outside of the defensive SP+ top 20. (The 2015 unit ranked 34th; oh, the shame and horror.) But the Tigers currently rank 37th, seven spots below Oklahoma (MORE SHAME), and the primary cause is a front seven that just doesn't throw opponents off course enough. LSU ranks 46th in stuff rate and 97th in sack rate. No Tigers defender has more than four tackles for loss or two sacks. The secondary is very disruptive, but that doesn't really matter if opponents don't have to pass.

If ... Joe Burrow gets the ball out a bit faster.

You have to nitpick to find anything wrong with the LSU offense, but it does bear mentioning that the Tigers rank only 47th in sack rate allowed, 78th on standard downs. Burrow is extremely comfortable in the pocket, and as with Fields, that sometimes turns into "too comfortable." One could see a particularly good pass-rushing defense (something the SEC West strangely lacks this season) taking advantage of that.

Georgia (5-1)

SP+ ranking: 7

FPI ranking: 6

FPI national title odds: 1.7%

If ... the big-play faucet gets turned on.

LSU has proved that adding modernity and aggression to your offense can reap massive dividends, in terms of both aesthetics and success. Georgia, however, still likes to play things safe.

Despite a boundless number of blue-chippers, UGA is 94th in marginal explosiveness. When the Dawgs have to be aggressive, it looks pretty good on them, but they don't do it until forced to.

But hey, since they have to win out now to reach the CFP, maybe that means they'll feel the need to stay aggressive.

If ... the long-promised disruption makes more of an appearance.

Heading into spring ball, Bulldogs coach Kirby Smart made constant references to "havoc rate" -- which is, as I calculate it, your total tackles for loss, passes defensed and forced fumbles divided by total plays -- and how he wanted his defense to increase its disruptiveness.

After ranking 75th in havoc last season, the Dawgs have improved to 35th, but most of that improvement has come from the secondary. Georgia is 73rd in stuff rate and 79th in sack rate, and in its two closest games, it made just three TFLs in each. That's not enough.

Jalen Hurts and the Sooners want to be better in the red zone. Ronald Martinez/Getty Images

3 Ifs

Oklahoma (6-0)

SP+ ranking: 3

FPI ranking: 7

FPI national title odds: 7.1%

If ... the run D's mistakes aren't catastrophic.

Under new defensive coordinator Alex Grinch, the Sooners are 17th in success rate allowed against the run. They have, however, allowed 11 rushes of 20-plus yards (99th in FBS) and 28 overall gains of 20-plus (68th). If they're not stopping you for a 2-yard gain, you're potentially running a long way.

This can work out fine as long as the efficiency levels are high, but if there's any slippage there, the big plays could quickly become costly.

If ... the red zone defense improves.

Despite the efficient run defense, the Sooners are 52nd in points allowed per scoring opportunity, 93rd in success rate allowed inside the 10, and 105th in first-and-goal success rate.

If ... those red zone turnovers weren't a harbinger.

Jalen Hurts has thrown just three interceptions, and his two fumbles are a pretty small number for a QB. But his carelessness in the red zone against Texas -- he threw a pretty foolish interception in the end zone, very nearly threw another and lost a fumble as well -- were at least a small red flag. Turnovers are random and don't have to be predictive, but that has to get cleaned up.

Wisconsin (6-0)

SP+ ranking: 4

FPI ranking: 5

FPI national title odds: 6.1%

If ... Northwestern Coan doesn't make another appearance.

Compared to expectations, quarterback Jack Coan has been a success thus far. Omitting the Northwestern game, he's completing 79% of his passes with eight TDs, no INTs and a 186.8 passer rating.

Against Northwestern, however, he looked like last season's Coan, throwing for 113 yards and a pick. Passer rating: 93.7. A playoff run will require at least one win over Ohio State, plus victories over good defensive teams such as Iowa and Minnesota. That version of Coan can't make another appearance.

If ... the Badgers have been hoarding big pass plays.

The Badgers' passing game hasn't been a liability, but it also hasn't helped from a big-play perspective. Wisconsin is 110th in passing marginal explosiveness; on blitz downs, the Badgers are 125th in big-play rate.

When you've got this ridiculous defense (four shutouts, second in defensive SP+) and Jonathan Taylor's absurdly efficient rushing, you don't need a ton from the pass. But at some point, getting some easy points from the passing game might be immensely helpful.

If ... a tight game doesn't come down to place-kicking.

Sophomore Collin Larsh has made just one of four field goal attempts beyond 30 yards. Yikes.

Can Sean Clifford play better against tougher competition? Randy Litzinger/Icon Sportswire

Penn State (6-0)

SP+ ranking: 6

FPI ranking: 8

FPI national title odds: 3.4%

If ... Sean Clifford improves against good defenses.

The PSU defense is on its way to its fifth top-15 finish in defensive SP+ in six seasons. The run game is growing more efficient as freshman Noah Cain takes on more carries. But to make a true title run, the Nittany Lions need their quarterback to play his part.

Penn State has played against two top defenses (Iowa is sixth in defensive SP+, Pitt 11th). In those two games, Clifford completed just 48% of his passes, with a dreadful 107 passer rating. He's been brilliant against everyone else (72% completion rate, 204 passer rating), but the Nittany Lions have three games left against top-10 defenses (Michigan, Michigan State, Ohio State). Can Clifford come through?

If ... the line does its part, too.

PSU's line looked totally overwhelmed in the first quarter against Iowa last weekend before righting the ship. Michigan's and Michigan State's defensive fronts are potentially even better.

If ... the pass defense becomes less all-or-nothing.

Penn State has a great pass rush (15th in sack rate) and efficient pass defense (eighth in passing marginal efficiency), but when there's a glitch, it's a huge one: The Nittany Lions are 73rd in passing marginal explosiveness and 89th in blitz down big-play rate.

4 Ifs

Notre Dame (5-1)

SP+ ranking: 21

FPI ranking: 11

FPI national title odds: 1.4%

If ... the run defense wakes up.

Despite a solid performance against Georgia, the Irish are 115th in rushing marginal efficiency. USC's running backs carried 27 times for 172 yards last week in a near-upset. The front seven are disruptive, but you can still run the ball on them.

If ... the playcalling plays better to strengths.

The Irish are 26th in rushing marginal efficiency and 79th in passing marginal efficiency, but they run the ball just 54% of the time on standard downs (92nd in FBS). It appears they could lean on their run game more. Maybe Tony Jones Jr.'s 25-carry, 176-yard performance against USC is a sign of things to come.

If ... ND simply stays on schedule better on both sides of the ball.

In open-play situations (snaps between your 10 and your opponent's 30), the Irish rank 88th in standard-downs success rate on offense and 50th on defense. Ian Book is catching back up to the chains better than opposing QBs, but the Fighting Irish are making life hard on themselves.

If ... the third-down D improves.

Notre Dame is 52nd in third-and-long success rate allowed, 49th on third-and-medium, 118th on third-and-short. Not good enough for a title contender.

Fields leads Ohio State to win with 3 TDs Justin Fields throws two touchdown passes and runs for another to propel No. 4 Ohio State to a 34-10 win over Michigan State.

Oregon (5-1)

SP+ ranking: 9

FPI ranking: 9

FPI national title odds: 1.1%

If ... the offense creates more easy points.

The Oregon run game hasn't gotten going, and neither run nor pass is creating enough big plays -- the Ducks are 76th in marginal explosiveness. And now quarterback Justin Herbert is without an extreme efficiency weapon in injured tight end Jacob Breeland.

Big plays create easy points. Oregon's lack of them is contributing to the next two "ifs" on this list, too.

If ... the red zone offense improves, and quickly.

The poor run game has probably contributed to a mediocre red zone effort: Oregon is only 60th in points per scoring opportunity and 88th in first-and-goal success rate.

If ... the Ducks get out of their own damn head on third down.

The Ducks are 127th in third-and-medium success rate on offense ... and the defense is only 80th. Half of third downs fall in this range, and Oregon is losing a majority of them.

If ... Andy Avalos fixes a risk-reward imbalance.

Avalos, the incredible new defensive coordinator, has the Ducks first in defensive SP+, but on blitz downs, they are just 53rd in success rate and 104th in big-play rate, which negates the effects of being 11th in sack rate.

Auburn (5-1)

SP+ ranking: 12

FPI ranking: 10

FPI national title odds: 1.0%

If ... Auburn stays on schedule (without JaTarvious Whitlow).

Gus Malzahn has taken back playcalling duties this season, and while there have been some bright moments, Auburn is still only 71st in standard downs marginal efficiency. And now it is without Whitlow, its best running back (injured knee). The Tigers are putting freshman quarterback Bo Nix in too many obvious passing situations, and it's creating the next "if" on the list.

If ... the offense punishes blitzers more.

On blitz downs, the Tigers are wholly mediocre: 65th in success rate and 94th in big-play rate. They face more of these than you'd prefer, and they don't respond to the challenge.

If ... the pass rush picks up.

The Tigers are 12th in defensive SP+, but they're not getting to the passer like they have in recent seasons: They're 48th in sack rate, 89th on blitz downs. That's creating another costly issue ...

If ... the defense can get off the field.

Auburn dominates standard downs (eighth in SD marginal efficiency) but repeatedly lets opponents off the hook (108th in passing downs marginal efficiency, 88th in third-and-long success rate allowed). One could see how this might be an issue in battles against Joe Burrow and Tua Tagovailoa still to come.

Matt Rhule has Baylor back in the Top 25. Jerome Miron/USA TODAY Sports

Baylor (6-0)

SP+ ranking: 16

FPI ranking: 25

FPI national title odds: <0.1%

If ... the run game keeps improving.

Baylor's offense ranks seventh in Passing Downs SP+. Quarterback Charlie Brewer is a hell of a situational playmaker, but it would be great if he didn't have to prove himself so frequently. Baylor is only 43rd in Standard Downs SP+, thanks primarily to a run game that ranks 50th in marginal efficiency and 84th in stuff rate. This has improved with John Lovett taking a majority of the carries recently. It has to continue improving.

If ... the defense stops letting teams off the hook.

Coordinator Phil Snow's defense is awesome at forcing teams off schedule, but you've gotta close the deal. The Bears are 62nd in passing downs marginal efficiency and 117th in blitz downs success rate.

If ... third-and-mediums are friendlier.

In third-and-medium success rate, Baylor ranks 102nd on offense and 65th on defense. A whole bunch of games will be won down the stretch by teams that can actually convert third-and-5.

If ... special-teams clutch opportunities are about done.

John Mayers knuckled in a tying field goal late against Texas Tech; he also nailed a winner against Iowa State. Clutch! But he has also missed two FGs under 40 yards, and Baylor ranks just 111th in overall special teams SP+.

Minnesota (6-0)

SP+ ranking: 17

FPI ranking: 29

FPI national title odds: <0.1%

If ... this October renaissance is real.

After skating by early in the season and briefly falling to 50th in SP+, the Gophers beat Illinois and Nebraska by a combined 74-24 the past two weeks and have surged to 17th in SP+. The running game the Golden Gophers have been trying to establish all season has ignited (Rodney Smith and Shannon Brooks in these two games: 560 combined yards).

Minnesota will have every chance in the world to prove itself, facing Penn State, Iowa, Northwestern and Wisconsin in November. But the new Gophers have to be the permanent Gophers.

If ... the run game in particular is permanent.

Despite these two brilliant games, Minnesota still ranks only 59th in rushing marginal efficiency and 85th in rushing marginal explosiveness.

If ... opponents fall off schedule a bit more.

Led by All-America candidate Antoine Winfield Jr., the Gophers' defense is brilliant on passing downs. But that matters only if you can force them, and Minnesota ranks only 95th in standard downs marginal efficiency.

If ... place-kicking, again.

The Gophers are unproven at best in this regard. Freshman Michael Lantz is just 4-for-6 on FGs and has been asked to attempt just one over 40 yards (he missed it).

Week 8 playlist

Here are 10 games -- at least one from each weekend time slot -- that you should pay attention to if you want to get the absolute most out of the weekend, from both an information and entertainment perspective.

All times ET.

Friday

No. 4 Ohio State at Northwestern (8:30 p.m., Big Ten Network). You're not watching this game to see if there's an upset in the works, you're simply watching to see how long the Wildcats, with a strong defense (fifth in defensive SP+), two weeks to plan and that tall Ryan Field grass, can confuse and/or slow down Justin Fields. For Michigan State two weeks ago, it was four drives.

SP+ projection: Ohio State 34, Northwestern 7

Early Saturday

Iowa State at Texas Tech (noon, Fox Sports 1). The good thing about a logjam like the Big 12's -- in which seven teams rank between 15th and 37th in SP+ -- is that every week features a series of super-tight, super-important games. Oklahoma State-Baylor might be the most impactful this week, but it's in a crowded time slot. Iowa State-Texas Tech could be great, too, though.

SP+ projection: Iowa State 29, Texas Tech 25

Saturday afternoon

No. 12 Oregon at No. 25 Washington (3:30 p.m., ABC). Strangely, 15 of the past 17 games in this series have been decided by at least 17 points, so maybe you don't have to watch this one for long. But the Ducks have a statement opportunity against a Huskies team that has alternated between top-10 and top-80 caliber this season.

SP+ projection: Oregon 26, Washington 25

Temple at No. 19 SMU (3:30 p.m., ESPN2). First Maryland, then Memphis. Temple has taken down two ranked teams this season and now gets a shot at a third. The Owls' defense is as good as ever (18th in defensive SP+), but SMU's offense has plenty of firepower itself (34th in offensive SP+), at least if receiver Reggie Roberson Jr. is healthy enough to go.

SP+ projection: SMU 27, Temple 24

North Carolina at Virginia Tech (3:30 p.m., ACC Network). Our quest for a six-way tie at 4-4 in the ACC Coastal continues. Last week, we needed Miami to beat Virginia, and the Hurricanes complied. This week, the most important result -- again, per my friend Justin Moore (@tfgridiron on Twitter), who ran a million simulations (we're nerds) -- is Tech taking down UNC. Go Hokies.

SP+ projection: Virginia Tech 30, North Carolina 29

Saturday evening

No. 16 Michigan at No. 7 Penn State (7:30 p.m., ABC). The home team has won the past three games in this series by an average of 34.3 points. The Wolverines and Nittany Lions take turns making big statements here; with its surging rushing game and dominant run defense, is Penn State primed to continue the blowout streak?

SP+ projection: Penn State 28, Michigan 20

No. 17 Arizona State at No. 13 Utah (6 p.m., Pac-12). Utah remains the best team in the Pac-12 South, but Arizona State has steadily improved, from 45th in SP+ a month ago to 33rd now. The Sun Devils should be able to stand up to the Utes' offense and make this interesting, but Utah has also played merciless football since the loss to USC.

SP+ projection: Utah 32, ASU 21

Tulane at Memphis (7 p.m., ESPN2). One of my favorite stories of 2019, Tulane has surged from 74th to 38th in SP+ over the past month, but Memphis has ranked in the 20s for most of the season. Can the Tigers bounce back from an annoying loss to Temple, or do they get sucked undertow by the Angry Wave?

SP+ projection: Memphis 33, Tulane 24

North Carolina A&T at Florida A&M (6 p.m., ESPN3). A&T has become a Celebration Bowl mainstay, attending the game three of four years. If the Mid-Eastern Athletic Conference is going to produce some new blood, this could be the best opportunity -- FAMU has won five in a row and is coming off of a key victory over South Carolina State. Upset time? (SP+ doesn't think so.)

SP+ projection: North Carolina A&T 29, Florida A&M 20

Late Saturday

Air Force at Hawai'i (11 p.m., CBS Sports Network). Honestly, the best game of the evening might be FCS No. 6 Montana playing at quickly rising Sacramento State, but if you don't feel like streaming that one, take a trip out to the islands. There should be plenty of points to go around.

SP+ projection: Air Force 36, Hawai'i 31