by Tom Gower

Denver Broncos

Biggest Offseason Hole: Secondary

Tim Tebow has occupied most of the conversation concerning the Broncos since he became the starter six games into the 2011 season. Tebow was inefficient. As a passer, he ranked 37th among 46 quarterbacks by DVOA, and as a rusher, he surprisingly ranked just 34th among 41 quarterbacks. Tebow ran the ball 42 times on third or fourth down, and only made it to the sticks for a new set of downs 13 times.

However, Tebow is far from the only young quarterback in the league who needs to improve for his team to see serious improvement on offense, and it’s worth giving him the benefit of the doubt for another season since he didn’t have a full offseason to work with John Fox and Mike McCoy.

The Broncos’ biggest problem instead comes in the defensive backfield. Champ Bailey is still one of the league’s best cornerbacks, but will be 34 by the start of the 2012 season. While 2008 was the only season where he missed significant time, he has only played 16 games once in the past five seasons, and age is likely to take an increasing toll on his availability and level of play. The other starting corner, Andre’ Goodman, had a surprisingly decent season, but will be 34 as well by the start of next season. There are no clear replacements for either on the roster. Rookie Chris Harris had a good year as a nickelback, but is probably not ready to start. The only other corner who saw significant action was Cassius Vaughn, who graded poorly in our game charting project before going on injured reserve.

At safety, the biggest problem will be replacing strong safety Brian Dawkins. The veteran ex-Eagle was effective, primarily in underneath coverage, but is 38, and a late-season neck injury may force him to retire. Unlike at corner, the Broncos do have a couple young players on the roster who may compete for playing time: third-year player David Bruton and 2011 draftees Rahim Moore and Quinton Carter, who all split time at free safety.

If Dawkins doesn’t come back, a reasonably-priced veteran strong safety would be a good priority for the Broncos in free agency. With Goodman and Bailey in place, at least for now, the Broncos could pass on paying to dollar for a corner in free agency and opt to choose one with a high draft pick and the intent of installing him as a starter in 2013.

Kansas City Chiefs

Biggest Offseason Hole: Re-establishing 2010’s Core

The Chiefs’ surprising trip to the top of the AFC West in 2010 was keyed by the contributions of a number of important young players. This core included:

A little over one year removed from the playoff loss to the Baltimore Ravens, the status of each of those players as a core member of the Chiefs is in question.

Moeaki, Charles, and Berry each suffered an ACL tear that caused him to miss all or almost all of 2010. The Chiefs were planning on a big role for Moeaki in 2011, but his history of injury problems extends back to college and was a big reason he fell to the fourth round in 2010. Charles was perhaps the league’s most explosive back in 2010, and without him the Chiefs fell from third and eighth in Second Level Yards and Open Field Yards, our key measures of running back explosiveness, to 25th and 27th, respectively. Berry showed preternaturally good instincts at free safety as a rookie in 2010, but any lingering effects from his ACL injury could slow him just enough to make a pass defensed in 2010 into a pass completed in 2012.

Both Bowe and Carr are scheduled to become unrestricted free agents if the Chiefs do not re-sign them by March 13. The Chiefs acquired Steve Breaston and Jonathan Baldwin at wideout last offseason, but right now, both players look better served as complements behind Bowe and not the cornerstones of a passing offense. Carr is probably not quite as good as the other starting cornerback, Brandon Flowers, but is still a very good player in his own right. Carr has averaged 7.0 and 6.9 yards per pass in our game charting project the last two years, which ranks him in the upper half of starting outside cornerbacks.

The Chiefs thus could be at a bit of a crossroads. If Moeaki, Charles, and Berry return to form, and they retain Bowe and Carr, then with the right moves around them the team could be competitive for several years to come. If Bowe and Carr are allowed to depart in free agency, though, and Moeaki, Charles, and Berry are permanently slowed by their injuries, then the Chiefs’ building process could be delayed several years.

Oakland Raiders

Biggest Offseason Hole: Linebacker

Despite the rocky start to Carson Palmer’s tenure, the Raiders’ offense improved from 2010 to 2011, as they rose from 23rd to 14th in our DVOA ratings. Had the defense maintained its league average performance from 2010, when it ranked 15th, instead of falling to 26th, the Raiders probably would have won at least one more game and taken the division for the first time since their Super Bowl appearance in 2002.

For the Raiders to improve on defense, they’ll have to upgrade the talent on the defensive back end. The first place to look may be at middle linebacker, where it’s fair to characterize Rolando McClain, the eighth overall selection in the 2010 NFL draft, as a disappointment. At his best, he’s a thumper who fills the hole well, but he does not make many plays at or behind the line of scrimmage, nor does he have the range to make as many plays as most middle linebackers. He was also targeted in pass coverage more than any other linebacker in our game charting data, with mostly middling results.

Unfortunately for the Raiders, McClain was probably their best cover linebacker. Outside linebacker Kamerion Wimbley is a pass rusher who rightly kicked down to defensive end in obvious passing situations. Aaron Curry, who started after being acquired via trade from the Seahawks during the season, is one of the least instinctive players in the NFL and should not be on the field in passing situations.

The Raiders do not have a pick in the first four rounds of this year’s draft, so any serious improvements will have to come in free agency. While in an ideal world, the Raiders find upgrades for both McClain and Curry, a more realistic solution might be replacing Curry with an outside linebacker that has the ability to play pass coverage, while playing even more dime personnel in obvious passing situations.

San Diego Chargers

Biggest Offseason Hole: Cornerback

In 2010, the Chargers missed the playoffs despite an excellent offense and defense because of historically bad special teams play. In 2011, the offense was still very good while the special teams improved to merely below average (23rd in our DVOA ratings), but the Chargers once again missed the playoffs because the defense declined. The biggest problem was pass defense, where the Chargers declined from -6.2%, fourth in the league, to 27.6%, 31st in the league.

The most inconsistent play the Chargers received came at cornerback. Antoine Cason had an up-and-down season, giving up some big passes, but overall came out fairly well in our game charting statistics. On the other side of the ball, Quentin Jammer did not come out so well. The veteran was one of the few cornerbacks whom our game charting project rated as giving up an average of at least 10 yards per play. Jammer has had an inconsistent career and is probably capable of a bounce-back season. Still, he will turn 33 before the 2012 season begins, and both he and the Chargers would be better off if he replaced Steve Gregory at strong safety.

If the Chargers do move Jammer to safety, the obvious candidate to replace him in the starting lineup is 2011 second-round pick Marcus Gilchrist. Our game charting, project, however, rated Gilchrist as giving up more yards per pass than even Jammer, and with fewer successful plays. An upgraded pass rush would help the entire secondary, but if they want the defense to return to an elite level, the Chargers should consider acquiring the best cornerback they can reasonably afford in free agency.

(This article originally appeared on ESPN Insider.)