Sacks: Jason Pierre-Paul
In just his second season, Jason Pierre-Paul led all defensive linemen with 86 tackles and was third with 16.5 sacks. The scary thought is that he could actually improve from year two to year three.
JPP will dominate the NFL once again and lead this team in sacks. He could possibly challenge Michael Strahan's record with Justin Tuck and Osi Umenyiora keeping the pressure off him.
Tackles: Antrel Rolle
Rolle led the Giants in tackles in 2011 with 96 and was second in 2010 with 87. He shined towards the end of last season when Perry Fewell simplified the defense. Rolle rarely comes off the field and is fantastic in run support—no reason to believe anyone else will lead the team in tackles.
Interceptions: Prince Amukamara
The Giants 2011 first-round pick did not get much of a chance to shine last season due to a broken foot, but with a full offseason and playing the nickel corner most likely, he'll see much more of the field in 2012.
Teams stay away from Corey Webster, so the other corners should get plenty of opportunities for interceptions.
Forced Fumbles: Osi Umenyiora
Ever the sack/fumble artist, Osi will get back to doing what he does best now that he is relatively happy after renegotiating his contract. He tied an NFL record with 10 sack fumbles in 2010 and had two more this season (tied for the team lead). As long as he doesn't lose too much playing time to JPP, which he shouldn't, he'll lead the team in this category once again.