Tyrann Mathieu, S, ARZ
Listed as a safety, Mathieu will presumably see extensive work as both a slot corner and a run-defending safety as a rookie this year. The third-round pick out of LSU has a legendary college resume, and he's been earning rave reviews throughout training camp. Listed behind Rashad Johnson at free safety, it's easy to see Mathieu forcing aging strong safety Yeremiah Bell off the field much of the time, and corners like Jerraud Powers, Javier Arenas and Antoine Cason might see the bench when it's time for Mathieu to play, too.
David Amerson, CB, WAS
Amerson likely will start for Washington by default and might not be particularly effective in real football terms, but the second-round pick out of North Carolina State is big (6-foot-1, 205) and athletic (4.44-second 40-yard dash), and his knack for allowing big plays is matched by his knack for filling up the box score (18 interceptions in his last two years of college). Even with the inviting DeAngelo Hall at one corner spot, Amerson figures to tempt opposing quarterbacks enough as a rookie to head into the year as a high-upside gamble in many formats.
Eric Berry, S, KC
Berry is coming off a weak 2012 season, his first year back from a 2011 ACL tear, but with another year of recovery he should be able to improve his 2012 total of 86 tackles and one interception. Not just that, but the Chiefs have experimented with allowing Berry to play linebacker in dime formations, and they also plan to increase his blitz opportunities. If he's 100 percent healthly as he should be, Berry has the range to make plays in coverage wherever he is on the field, and playing closer to the line of scrimmage can only aid his chances of making tackles.
Patrick Peterson, CB, ARZ
Double-check whether your league counts stats for IDPs that occur on offense, but if it does, Peterson could be a bit of a Joker card in your league this year. The Cardinals reportedly used him on offense in training camp to the extent that he's shown up on about 15 different play calls. It's doubtful that it will really amount to a substantial difference in his point total at the end of the year, but between his ability to score on punt returns and his evident potential to provide a few big plays on offense this year, Peterson could provide a few scoring outbursts in 2013.
Brandon Boykin, CB, PHI
Superior height and more expensive contracts made Cary Williams and Bradley Fletcher the favorites to start at cornerback over Boykin this year, but both of Philadelphia's free-agent cornerback additions have failed to impress in training camp. Boykin, meanwhile, has made enough of an impact to push his way into the starting cornerback discussion, probably at the expense of Fletcher, who failed to make much of a mark in his four years with the Rams. Boykin should serve as Philadelphia's kick returner this year and, if he earns a starting role as well, he should be useful heading into this year. Despite a quiet rookie season, Boykin showed a lot of disruptiveness as a tackler at Georgia, making 17.5 tackles for loss in his final two years with the Bulldogs.
Sean Weatherspoon, LB, ATL
Weatherspoon suffered a "badly dislocated finger" Monday, which appears rather gruesome at a glance. The Falcons deemed Weatherspoon "out indefinitely," which is not the prognosis we want to hear with the season opener less than a month away. Weatherspoon is a highly disruptive and very talented linebacker, but injuries have blocked him from ascending to the top tier of linebacker IDPs.
Bruce Irvin, OLB, SEA
Irvin's four-game suspension was in itself a painful strike to Irvin's IDP value. His move from defensive end to outside linebacker, though, firmly negated all of it. Irvin won't steal many tackles from Bobby Wagner and K.J. Wright at linebacker, and he probably won't snatch many sacks away from Cliff Avril and Michael Bennett in pass-rush situations. With an LB designation in IDP leagues, it seems like Irvin has very little chance of making an IDP impact in 2013. It doesn't help that he's expected to miss Seattle's first preseason game Thursday with a groin issue.
D.J. Williams, MLB, CHI
Williams' past success would seemingly make him the favorite to emerge as Chicago's second nickel linebacker next to top dog Lance Briggs, but a calf injury suffered early in training camp threatens to let fellow free-agent addition James Anderson (Carolina) and perhaps even second-round pick rookie Jon Bostic gain some ground on Williams. Williams is "week-to-week."
John Abraham, (3-4) OLB, ARZ
Abraham could have presented value as a defensive end, especially in leagues that reward heavily for sacks, but by signing with Arizona he all but assured that he'll be a non-factor as an IDP this year. Not only might he play behind Sam Acho, Lorenzo Alexander and Matt Shaughnessy for snaps, but there's basically no chance that Abraham puts up the necessary tackle numbers to maintain relevance with an LB designation.
Daryl Washington, (3-4) ILB, ARZ
Washington's potential suspension for 2013 is nothing new, but it's worth a reminder as we head into this year that Washington, previously one of the most elite IDPs at any position, will miss the first four weeks of the year barring a successful appeal. The odds of that happening seem rather slim because Washington has no leverage against his four-game PED-related suspension, especially when you factor his alleged domestic violence incident from May.