Wide Receiver: It's worth noting that veterans Ruvell Martin and David Clowney saw playing time before a trio of younger players (Marcus Easley, Naaman Roosevelt and Kamar Aiken) did. That may not mean much in terms of how the team views those five receivers in particular, but T.J. Graham did work in before those two veterans, giving clear indication that the team is fast-tracking him not just for a roster spot, but for a potential role.
Tight End: In a bit of a mild upset, project player Fendi Onobun was the third tight end on the field, coming in ahead of Kevin Brock, who was talked up a bit prior to training camp by the team. Onobun is an excellent athlete, and the Bills appear to be interested in giving him lots of reps to see what he can offer on the football field.
Offensive Tackle: Sam Young may be giving rookie Zebrie Sanders a run for his money to be the fourth tackle on the final roster. Young has gotten a lot of extra reps in camp thanks to injuries, and he played both left and right tackle in the pre-season opener, while Sanders was stuck on the right side. That added versatility that Young apparently offers could make him a more valuable keep than Sanders, who still undoubtedly has the higher upside.
Guard/Center: Here's the list of players that worked into the lineup well ahead of fan favorite Michael Jasper: Colin Brown, Mark Asper, Keith Williams, David Snow and Jake Vermiglio. That's every other guard/center on the roster, folks. Jasper may still be worth keeping around on the practice squad, but if you were holding out hope that he'd make the team outright, it's time to let that dream die.
Defensive Line: A lot of the rotation went as expected, with one minor exception being end Kyle Moore getting some reps with the second unit. That may have been a function of getting a trio of vets out of the game quickly, but Moore was lining up across from Shawne Merriman, so it's at least worth noting. Moore got into the game well ahead of third-team tackles Alex Carrington and Kellen Heard.
Linebacker: Perhaps in an effort to keep Kelvin Sheppard fresh, Scott McKillop got some first-team reps at middle linebacker. The only other noteworthy development deeper on the depth chart: Chris White worked in ahead of both Tank Carder (who was a first-unit special teamer) and Danny Batten. Batten may be the true longshot at linebacker.
Safety: If the Bills eventually do sign a fourth reliable safety, this rotation may become irrelevant. For now: Nick Saenz got second-team reps at free safety, then Nick Sukay, Joshua Nesbitt and Delano Howell worked in.