"I think it's going to be mixed reactions," Posluszny said. "I loved being in Buffalo. ... But let's be honest, I'm the enemy."
"Paul is a great dude. He was really respected in the locker room," Fitzpatrick said of Buffalo's 2007 second-round draft pick. "I think everybody's excited just to see him to say, 'Hi.' I'm just hoping he doesn't hit me at all."
Whether or not that happens is among the key tests in gauging the progress of both teams two weeks before the start of the season.
Protecting the quarterback has become one of the primary concerns in Buffalo, where the offensive line is being questioned for its lack of consistency and depth. The latest question mark is left tackle Demetrius Bell, who is being challenged for the starting job by left guard Andy Levitre.
For the Jaguars, Posluszny is part of a revamped defense counted upon to take a big step forward from last year, when it finished No. 28 in yards allowed and had difficulty in applying pressure.
Posluszny, for one, is up for the challenge and eager to start earning the six-year, $45 million contract he agreed to within 24 hours after the NFL lockout was lifted.
"They're on the winning path," Posluszny said. "I know last year they were a couple of games short of the playoffs, and that's something that I haven't experienced yet in my career, being in the middle of a playoff run."
Despite their struggles on defense and questions at quarterback, the Jaguars were in contention before losing their final three games that led to an 8-8 finish. That's significantly better than Posluszny's four seasons in Buffalo, where the Bills won no more than seven games before going only 4-12 last year.
All it takes for Posluszny to see the Jaguars' commitment to improving is to look at the newcomers playing around him.
"It definitely is proving to us that they want to do everything they can to win," he said. "Now, it's our job to go out there and compete and play to the best of our abilities."
Posluszny wasn't necessarily part of the problem in Buffalo, where he was a four-year starter and led the team in tackles in each of the past three seasons.
The Bills are a team in transition, having spent much of the offseason revamping a defense that ranked last against the run last season.
Buffalo used seven of its nine draft picks on defensive players, starting with selecting lineman Marcell Dareus third overall.
The Bills moved quickly to replace Posluszny by signing eight-year veteran Nick Barnett. He'll be part of a new-look group of linebackers that also features pass-rushing specialist Shawne Merriman, who did not play for Buffalo last season after being acquired off waivers in November.
Merriman is nursing a groin injury and is considered questionable to play Saturday. Buffalo lost backup inside linebacker Reggie Torbor to a season-ending shoulder injury this week.
Torbor will be replaced by Kirk Morrison, a six-year veteran and a former Jaguar who signed a one-year contract Friday.
As much as veteran Andra Davis misses playing alongside Posluszny, he's more than comfortable with Barnett.
"Nick's been a wonderful pickup. There's nothing he can't do. He's physical, fast, smart. He's seen it all," Davis said. "Bringing in Nick, you're definitely not losing any steps."
Copyright 2011 by The Associated Press