Week 4 wasn't especially kind to the IDP world, as a number of important players went down with significant injuries.

Trent Cole (calf strain), James Harrison (orbital bone fracture) and Jerod Mayo (MCL sprain) all suffered multi-week injuries, while Justin Tuck's neck condition worsened to the point that he might be on a week-to-week basis, too.

Harrison's injury, in particular, is damaging to the IDP talent pool, as his absence prompted Pittsburgh to move Lawrence Timmons outside, basically negating Timmons' IDP value as long as Harrison is out. Timmons is unlikely to rush the passer as well as Harrison, and he'll see significantly fewer tackle opportunities on the outside, too.

Joining Timmons on the Fallers list are London Fletcher and Derrick Johnson, both of whom are on pace to fall short of triple-digit tackles. Meanwhile, expect Jason Babin to see more double-teams in Philadelphia for as long as Cole is out of the picture.

Although the values of Timmons, Fletcher and Johnson are pointed downward, Week 4 saw at least one young linebacker jump in on the IDP conversation. Pat Angerer made the list last week as he took the league lead in tackles, and this week his teammate Kavell Conner joins him. The two rank first and second in the league in tackle totals, respectively.

Kavell Conner, LB, IND

Fellow Indianapolis linebacker Pat Angerer continues to lead the league in tackles with 50 (30 solo), but Conner raced up to second in line with an 18-tackles (14 solo) showing against Tampa Bay on Monday. He has at least 10 total tackles in three straight weeks, and even has two passes defensed and a forced fumble in that span. It's rare for a player to post tackle quantities like that and then disappear, so Conner is worth picking up in almost all scenarios.

Reggie Nelson, S, CIN

Nelson may have been a big bust for Jacksonville since the team selected him in the first round of the 2007 draft, but he's off to a strong start in Cincinnati this year. Through four games he has 30 tackles (22 solo), one sack, three passes defensed and four fumbles. These are the first signs of life he's shown his entire career, so he's not a must-add by any means, but he is someone to pick up if you need help in the secondary and are looking for some cheap upside.

Jason Pierre-Paul, DE, NYG

Pierre-Paul's value was already quite high, but with Justin Tuck's apparently-worsening injury situation, he moves as high as the top five on the defensive line. He's on pace for 88 tackles and 18 sacks through four games and should continue to put up big numbers as long as he's playing a role as a clear starter.

Jairus Byrd, S, BUF

Byrd came into the league in '09 a converted cornerback, and his rookie season numbers reflected that general skill set -- he was a magnet to the football when it was in the air, but he seemed somewhat allergic to ballcarriers, totaling nine interceptions in 14 games compared to just 45 tackles (33 solo). He seems to have done somewhat of a 180 since then, though, totaling 89 tackles (62 solo) and just one interception in '10 and making 34 stops (26 solo) with no interceptions through four games this year. Byrd would be an elite IDP if he could recapture some of his rookie-season ball-hawking ability, but in the meantime he looks like a good bet to put up big tackle numbers, at least.

George Wilson, S, BUF

Anyone who has kept an eye on Wilson over the years figured he would post good numbers this year, but his stats have been exceptional to this point. Taking over the role previously held by Donte Whitner, Wilson has 36 tackles (25 solo), two interceptions and a forced fumble through four weeks. While there's definitely something to be said for the scheme in Buffalo -- all of Wilson, Byrd and Whitner have now posted big numbers at safety -- Wilson might be the best of the bunch. His production isn't going anywhere.

Justin Tuck, DE, NYG

Due to his lingering neck injury, Tuck said on Thursday that sitting out through the Giants' Week 7 bye week "sounds like the smart thing to do," implying that he could be out four straight games (including last week's matchup with Arizona). That would obviously be a painful development for Tuck's IDP owners, though it would boost the value of Jason Pierre-Paul and Osi Umenyiora.

Lawrence Timmons, LB, PIT

After accumulating 135 tackles (96 solo), three sacks, nine passes defensed, two interceptions and two forced fumbles a year ago, Timmons' IDP stock was sky high entering '11. Unfortunately, he has disappointed with just 25 tackles (18 solo) through four games, and things figure to get even worse in light of Harrison's orbital bone fracture. Timmons will replace Harrison at outside linebacker, resulting in far fewer tackle opportunities from here.

London Fletcher, LB, WAS

Fletcher's defense has been on the field for only 234 plays, which ranks 29th in the league, but he has still been a big letdown from an IDP perspective so far this year. His total of 22 tackles is unimpressive, but his total of just 10 solo stops is almost a bit pathetic. He averaged 94.5 solo tackles per season in his previous four years in Washington, but he's on pace for just 40 this season. If he doesn't get going in the next couple weeks, he might fall off the IDP radar in most leagues.

Derrick Johnson, LB, KC

Considering the Kansas City defense is tied for the eighth-most snaps played in the league, Johnson's total of just 23 tackles (20 solo) though four games is quite disappointing. He broke out last year with a 120-tackle (95 solo) showing, but he's on pace for just 92 this year. The good news for his owners is that the team figures to keep spending a lot of time on the field, so the opportunities should remain for Johnson.

Jason Babin, DE, PHI

This entry isn't meant to make Babin's owners panic -- they should definitely hold on to the NFL sack leader. But it is meant to be a heads-up that Babin's production is due to slow down a bit in the short term. His seven sacks likely would have earned him more attention from opposing offensive lines anyway, but the fact that Trent Cole (calf) is out of the picture for at least a couple weeks means teams can really start singling out Babin. Double-teams are mostly new to Babin, who was previously a first-round bust before breaking out in his eighth season under defensive line coach Jim Washburn's watch.

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