The Bills made their way through one of their most difficult practices to date Friday as they worked under the scorching hot sun at St. John Fisher. The temperature was just under 90 degrees Fahrenheit, and coach Chan Gailey was glad to see his team push through the session.

“You’d take more than one (hot practice) and we’re supposed to get another one tomorrow, so it’ll be good,” he said. “You have to fight through mentally and physically days like today. Four practices in a row in pads, an afternoon practice after a night practice, you have to fight through that and I told the players that. You gain toughness for finishing in the fourth quarter in December now, so hopefully we’re using this as a building block.”

Case of the drops: Buffalo’s receivers collectively had a rough go on Friday with several drops. “Not a little case, a huge case of the drops,” Gailey said. “Quartebacks had to be -- they would never say it, but I’ll say it for ‘em -- that’s unacceptable. We can’t have that. We drop the ball that much, we won’t win any games.”

What stood out: While it’s tough to critique the running game when contact is limited, both Fred Jackson and C.J. Spiller look as good as ever. Spiller is extremely quick, and even with Jackson as the starter he’s likely to have a significant role on offense this season. ... Receiver David Clowney has struggled throughout camp but had his best day yet. Clowney caught a nice touchdown pass from Vince Young in the left corner of the end zone during team work; he still has little chance of making the team. ... Young had some nice throws working with the second unit. ... Jackson ended the session with a short touchdown reception in red-zone work as the game clock expired.

First camp scuffle: It’s no surprise that tempers flared underneath the hot sun. Massive guard Michael Jasper and defensive end Robert Eddins exchanged blows during a break in team action, with a Jasper left hook cleanly knocking off Eddins’ helmet. The scuffle ended shortly after that.

Injury update: Three key starters -- Steve Johnson, Fred Jackson and George Wilson -- all suffered minor bumps and bruises at Friday’s practice. Johnson left practice with tightness in his groin; Gailey said afterwards that it was not the side Johnson had surgically repaired. Jackson and Wilson got stepped on but were able to finish practice. LB Kelvin Sheppard (undisclosed) participated in team work for the first time since July 31. DE Mark Anderson (groin) was limited. WR David Nelson (knee), S Josh Nesbitt (undisclosed), DT Kellen Heard (ankle), LB Bryan Scott (thigh), DE Chris Kelsay (groin) and TE Mike Caussin (knee) did not participate.

McGee update: CB Terrence McGee has been very limited so far at camp as he makes his way back from patella tendon surgery. Most days, McGee exits practice early and can be seen with an ice pack wrapped around his knee. Gailey provided this update after practice on McGee’s status: “Getting a little better. He couldn’t play if we had to play today. But he’s getting a little better. It’s not big leaps, no major breakthroughs. It’s little gains that we’re making right now.”

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