Posluszny, Buffalo's second-round draft pick out of Penn State, played middle linebacker with the first unit for most of the week and looked solid most of the time.
Posluszny practiced with the first unit because second-year player John DiGiorgio has been hampered by a hip flexor. DiGiorgio practiced with the second team Saturday.
"Our plan for John was to get him warmed up, get him back in the seven-on-sevens," Jauron said. "Hopefully, he'll get this day-and-a-half off and be ready when camp reopens Monday."
Posluszny was excited about working with the top unit.
"Practicing with the No. 1 group is the most important thing," Posluszny said. "The more I'm able to get together with them, the better I'll be."
A first-team Associated Press All-American for the Nittany Lions last season, Posluszny said there are many adjustments to make in the jump from college to the NFL.
"One of the biggest things is the speed of the game," he said. "In college, you may have that extra second to decide where to go. That's not the case up here."
But Jauron is confident Posluszny has the tools to make it in the NFL.
"He's a very sharp guy and he works at it," Jauron said. "It's a lot of new learning."
Posluszny, an academic All-American at Penn State, is aware that there's still a long way to go.
"Mentally, the toughest part is picking up the playbook and making decisions very quickly. It's tough, it's physical, but it's what I expected," he said. "I think I held my own with the first team. But to be a great player in this league, you need to have a lot of experience. And I'm getting more each day."
Notes:Bills TE Ryan Neufeld injured a knee during practice, but walked off the field. ... OL Jason Peters missed most of practice with what Jauron termed a sore calf. ... P Brian Moorman was excused from camp for what Jauron described as personal business. ... The Bills are off Sunday before returning for one session Monday night.
Copyright 2007 by The Associated Press