Start and sit decisions will win and lose you fantasy games this year. They’re very important, but not always very obvious. A myriad of factors have to be taken into consideration, including player talent, health, game flow, and matchups. For evaluating matchups against your wide receivers, you have to look not only at the quality of the entire defense, but the quality of the cornerback(s) that will covering them. It’s important to remember that this is only a small piece of the puzzle, however. If you’re looking at a player like a healthy Julio Jones you shouldn’t be considering who’s guarding him before inserting him into your lineup, but when there’s a tough decision to be made, make sure to give it some consideration. Let’s take a look at the league’s top cornerbacks and when it’s advisable to avoid them:

Cornerbacks To Avoid

These guys are the elite of the elite and should be avoided within reason.

Vontae Davis – IND

Abe and I keyed in on Davis’s dominance very early last year on the SmartCheatsheet podcast, where the shaky Colts defense was tricking people into starting receivers against the late-blooming elite cornerback. Things didn’t typically go well for those receivers. His streak of shutting down studs has continued into 2015, where Sammy Watkins totalled a whopping zero catches in a week 1 game in which the Bills were actually able to move the ball.

Since being traded from Miami in 2012, Davis has improved immensely every year and is just entering his prime. He was Pro Football Focus’s #2 rated cornerback last year, and opposing quarterbacks managed a pitiful 41.2 passer rating when targeting him (with zero touchdowns). According to Coach Chuck Pagano, Davis may be asked to shadow the opposing team’s #1 all game this year after staying mostly on the right side in 2014. This is definitely something to keep an eye on when making your lineup decision.

Darrelle Revis – NYJ

Revis Island is still a lonely place. After a fantastic 2014 season that ended in a Super Bowl victory, Revis is back on his original team with a revamped defense and coaching staff. At age 30, he’s lost a tad bit of the quickness and speed that made him completely untouchable, but still deserves the respect we’re used to giving him as a top three corner in the league. According to Football Outsiders, Revis was targeted a league low (for #1 corners) 17% of offensive pass plays last year, totalling a miniscule 69 balls thrown his way in 16 games. I don’t think any of us would be happy with a #1 receiver that totalled 69 targets in a full season.

Although there have been several exceptions, such as Revis not shadowing T.Y. Hilton in last year’s AFC Championship game, #24 infamously sticks the #1 receiver. Since moving to a new team under a new coaching staff this season, there have been some questions as to whether that would remain his role, but all evidence points to the fact that it will be. Although Week 1 wasn’t a very good indicator (the Browns don’t really have a #1 WR), the Jets paid Revis HUGE money and will likely be expecting him to continue doing what does best. Head coach Todd Bowles also used his top corner Patrick Peterson in the same role the last few years in Arizona, and Antonio Cromartie (the other corner the Jets gave big money to this year) was injured in week 1 and will be on the shelf for a while. Look for Revis to stay on the #1 man and try to avoid him if possible. Even if your player is talented enough to beat him a few times, his quarterback will likely be looking elsewhere.

Richard Sherman – SEA

As outspoken and cocky as Sherman is, he sure can back it up. Even the best quarterback in the world refused to throw in his direction in a week one meeting between the Packers and Seahawks last year, and was reminded why on his first pass targeting Sherman in the NFC Championship game. Since he blossomed into an elite shutdown corner in 2012, Sherman has ranked in the top five of PFF’s coverage rankings every single year. He is as consistent as they come, and, unlike Revis, much closer to the beginning of his prime than the end.

At 6’3” and lacking elite speed, Sherman is much more suited to match up against traditional, bigger receivers. Small and quick receivers like T.Y. Hilton, Emmanuel Sanders, and Odell Beckham Jr. have traditionally had better luck than most against him, but even yet he still doesn’t get beat often. Those are all top 15 players, so you should probably be starting them anyway.

Unlike Revis, Sherman has traditionally stayed on one side of the field for the entire game. This has made it very difficult for fantasy owners to figure out who he will be guarding, but Seattle’s defense and secondary have been so good that you don’t necessarily need to know if he’ll be guarding your guy to know that points are going to be tough to come by. Things have changed this year, however, as Seattle lost CB Byron Maxwell to free agency, defensive coordinator Dan Quinn to the Atlanta Falcons, and are still without Pro Bowl SS Kam Chancellor (and could be for a while.) The shakeup has caused many to wonder if Sherman’s role will change, and if week one is any indication, it will. He only spent 36 of his 59 snaps against St. Louis in his usual role on the left side, playing the slot more than he has in recent memory. We’ll be watching the week two matchup against Green Bay to see if this is a pattern or a one-game quirk.

Chris Harris Jr. – DEN

A favorite of film aficionados and advanced stat geeks, Chris Harris Jr.’s reputation in the mainstream is finally starting to match up to his play. Considering all the “inhuman” talk that Adrian Peterson got after coming back from an ACL tear to lead the league in rushing in 2012, very little has been made of the fact that Harris put together an amazing 2014 season just eight months after tearing his. Pro Football Focus considers Chris Harris’s 2014 season to be the second-best cornerback season they have ever charted, and ranked him as the fourth-best overall player in the NFL (not to mention #1 cornerback). He gave up a whopping zero touchdowns, allowed ONE 50+ yard game, and was targeted on a tiny 17.2% of offensive pass plays (second only to Revis among #1 corners).

As amazing as those coverage numbers are, the scariest thing about starting a wide receiver against Harris may be the defense around him. He plays all over the field, so it may be tough to pin down who he’s going to be guarding before the game starts. If you start your WR against the Broncos and are lucky enough to avoid Harris, your prize will most likely be Pro Bowler Aqib Talib. The Broncos are deep and loaded at all levels of the defense. As Von Miller and Demarcus Ware have completely dominated the first two weeks of the season, we’re reminded that Denver has the best pair of corners AND pass rushers in the league. Add that to a struggling Denver offense that will most likely not be attempting to get into any shootouts, and the Broncos may just be the worst matchup for wide receivers this year.

Cornerback Matchups To Be Aware Of

These guys are either borderline-elite or up-and-comers and while you shouldn’t avoid all matchups, you should try to be aware of who they’re guarding.

Desmond Trufant – ATL

While the Atlanta defense has been a disaster the past two years, Desmond Trufant has quietly developed into one of the league’s top corners. He earned Defensive Rookie of the Year honors from PFF in 2013, and was graded out as their #6 overall corner in 2014. Considering Atlanta ranked near the bottom in every possible pass rush metric over the last two seasons, Trufant has been tasked with sticking on his man much longer than any other corner on this list. With Dan Quinn now the lead man in Atlanta, the Falcons defense came out looking completely different in their first half of their first game against Philadelphia. Trufant gobbled up highly-touted rookie WR Nelson Agholor to the tune of one catch for five yards. The defensive line has a few new faces, including #8 overall pick Vic Beasley, and if Atlanta can get even a mediocre pass rush we could be looking at a Richard Sherman-type season from Trufant.

Trufant tends to man the outside left cornerback position. I’m guessing he’ll be assuming the Richard Sherman role in Quinn’s defense.

Brandon Flowers – SD

A perennial top ten cornerback before a down season in 2013 (in which he ironically made his first Pro Bowl), Flowers was surprisingly released by Kansas City in 2014 and was promptly signed to a one-year “prove it” deal with San Diego. And prove it he did. While San Diego ranked a disappointing 25th in overall defense, Flowers’ play jumped their rank to 13th against #1 wide receivers. PFF graded Flowers graded as a top 15 corner in 2014, while FootballOutsiders Adjusted Success Rate metric put him at #6. The Chargers recognized his worth and signed him to a four year, 36 million dollar deal this offseason.

Flowers excels in a zone scheme, and although he is not a player to be completely avoided in fantasy on his own, he does play in a loaded secondary with promising second year man Jason Verrett and Pro Bowl safety Eric Weddle. They shut down Megatron and the Lions passing game pretty effectively in week one.

Sean Smith – KC

Smith, Flowers replacement as the #1 corner in Kansas City, is his polar opposite. Smith is six inches taller and almost 30 pounds heavier than Flowers and excels in man-to-man coverage. He was PFF’s fifth highest rated corner in 2014 (third in coverage) and was targeted on only 19.9% of opponents passing plays. Rookie Marcus Peters has filled in for Smith through the first two weeks this season as he serves a two game suspension, and has looked exceptional. Peters has two interceptions already and has stuck stride-for-stride with some of the game’s best receivers. Once Smith comes back for week three, the Chiefs will have an extremely talented CB duo to go along with one of the league’s most fierce pass rushes. Receivers will have a tough time against this group.

Brent Grimes – MIA

Grimes had a down year coverage-wise in 2014, but was absolutely dominant in 2013. Coming off a torn achilles, he recorded four interceptions and allowed zero touchdowns en route to a Pro Bowl invite and was PFF’s #2 rated corner (he was #3 in 2011). Despite the tough last year in coverage, Grimes did have five picks, and made what (in my and his opinion) would have been the play of the year had it not been for Odell Beckham’s insane catch. With Grimes healthy and Ndamakungh Suh and Cameron Wake harassing quarterbacks, I’m betting on a return to elite status for #31. Miami’s #2 cornerback situation is a little more shaky, so starting a #2 WR against them might be a decent bet.

Honorable Mentions

Joe Haden – CLE

While Haden has infamously shut down A.J. Green in their battles, that may have more to do with Andy Dalton’s failings than Haden’s status as an elite corner. He has not been a PFF top-ten graded corner since 2010, but he does have the skill and ability to blank a top receiver.

Xavier Rhodes – MIN

Rhodes has excellent size and speed and improved immensely under Mike Zimmer’s tutelage in 2014. He’s not elite quite yet, but is probably the most likely to jump into the top two categories out of any honorable mention corner. He’ll have a tough test this Sunday against Megatron.

Patrick Peterson – ARI

Once regarded as a top five cornerback (although many analysts would disagree that was ever valid), Peterson had an abysmal 2014 and needs a big year to put him back into that conversation. He has blamed his poor play last year on his undiagnosed diabetes, and we should see soon if that was the case. He got off to a good start in week one by limiting Saints WR Brandin Cooks.

Josh Norman – CAR

Norman had a breakout year in 2014 (4th in FootballOutsiders Adjusted Success Rate), and started off 2015 with a bang by shutting down Allen Robinson. He’ll be playing for a contract this year.

Stephon Gilmore – BUF

New head coach Rex Ryan has moved standout CB Corey Graham to safety, started rookie Ronald Darby in his place, and given Gilmore the “Revis role” in his defense. He’ll be shadowing opposing team’s top weapons, and may even get a crack at Gronk this week. Gilmore improved greatly from 2013 to 2014 and looks like he’s coming into his own in this absolutely loaded Bills defense. Proceed with caution with ANY players going against Buffalo.

Dominique Rodgers-Cromartie – NYG

PFF’s #6 corner in 2013 and #17 in 2014, DRC is a top ten cover corner if he can stay healthy. He did a great job in week one against Dez Bryant, but will have his work cut out for him this season with the Giants safeties being either rookies or terrible. Don’t avoid the Giants in fantasy, even if it means starting your WR against DRC.

Jimmy Smith – BAL

Smith has had trouble staying healthy recently, but it’s a night and day difference when he’s on the field for the Baltimore secondary. He did a great job against Demaryius Thomas in week one and even returned a Peyton Manning-thrown interception for a touchdown. The rest of the Ravens secondary is very weak, so keep an eye on who Smith is guarding.

What other cornerbacks should we be keeping our eyes on this season? Let me know in the comments or on twitter @SmartFantasyNFL!