With fellow DEs Chris Kelsay and Mark Anderson taking it easy due to minor injuries, Shawne Merriman received an increased number of reps Thursday -- and, boy, did he make them count.

Merriman was as explosive as ever off the edge and gave Buffalo’s tackles fits throughout the session. It was the second impressive practice in a row for Merriman, who appeared lightning quick on Wednesday night as well.

“He’s given great effort,” coach Chan Gailey said. “It looks like he’s got some quickness to him. His stamina’s good. Hopefully he’ll make the season and things will go well for him. I’m looking forward to seeing what he can do when we get really live.”

The afternoon’s other top performer was WR Derek Hagan. Ryan Fitzpatrick connected with the receiver on the prettiest deep ball of camp -- a 50-yard bomb on a deep post pattern -- that Hagan reeled in nicely. The play resulted in a 70-yard touchdown. Hagan looks like he firmly has a place among Buffalo’s top-five WRs.

What else stood out: Backup QBs Tyler Thigpen and Vince Young continue to struggle with consistency, but Thigpen in particular had an increase in positive plays Thursday. In 7-on-7 work he connected with T.J. Graham and Marcus Easley on accurate throws to his left; in team work, he found Naaman Roosevelt a couple times. ... C.J. Spiller was quick and elusive as a runner and a receiver. He caught a wheel route and took it upfield for a big gain on a busted coverage by the defense. ... Rookie tackle Cordy Glenn had perhaps his most difficult day of camp. In one-on-one drills, he was beaten badly by reserves Sean Ferguson and Kyle Moore. ... Moore, a former fourth-round pick of the Tampa Bay Buccaneers, has had some promising rushes in recent days.

Injury updates: LB Kelvin Sheppard returned on a limited basis; the Bills have not revealed the exact nature of Sheppard’s injury. On Sheppard, Gailey said: “It’s probably going to be a little bit of a slow process, we’ll see how he does. It may be tomorrow, it may be next week. I don’t know.” Kelsay and Anderson are nursing minor groin injuries; Kelsay sat out, and Anderson was limited. LB Bryan Scott was limited with a thigh injury. WR David Nelson (knee), CB Justin Rogers (hamstring), DT Kellen Heard (ankle), TE Mike Caussin (knee), WR Kamar Aiken (undisclosed) and S Josh Nesbitt (undisclosed) did not practice. 

For more updates, follow Bills correspondent Mark Ludwiczak on Twitter @CBSSportsNFLBUF and @MarkLud12.