Some things can't be learned in training camp. We won't really know how Doug Marrone's Buffalo Bills offense looks until Week 1.
But there are some things we can learn, like which player will win the Bills' starting quarterback job. (And the No. 2 receiver job. And the strong safety job. You get the idea.)
Here's a look at the big questions we're going to track for each AFC East team in camp. (To hear our division previews in podcast form, just click above or right here.)
Buffalo Bills: Will EJ Manuel be ready for Week 1?
Kevin Kolb doesn't want to be seen as a placeholder for Manuel, the team's first-round draft pick. But that's what Kolb will be in Buffalo. This is not an even competition. If all things are equal in August, Marrone has to go with the rookie.
Manuel hardly was seen as a finished product coming out of Florida State, but Kolb hasn't shown the ability to handle the pass rush at the pro level. The Bills clarified this competition by cutting Tarvaris Jackson before camp. Look for Kolb to start the preseason opener, with Manuel getting his chance the following week. This competition isn't about Kolb; it's Manuel battling himself to prove he's NFL ready.
Miami Dolphins: Are they done spending?
The Dolphins have some serious roster holes considering how much money they spent this offseason. The offensive line and secondary face more questions than they did one year ago. This is a team to watch when it comes to low-level veteran trades and waiver pickups when roster cuts are announced. The Dolphins still could use veteran help at left tackle, running back and cornerback, where it's uncertain how soon rookies Jamar Taylor and Will Davis can play.
New England Patriots: Which pass catchers will step up?
There were plenty of questions about the Patriots even before Rob Gronkowski's latest back surgery and Aaron Hernandez's release. The Patriots' wide receiver group currently looks like Danny Amendola and everyone else. Guys like undrafted rookie Kenbrell Thompkins have as good a chance to play as veteran flotsam like Michael Jenkins. (Donald Jones already was cut). Mid-round draft picks Aaron Dobson and Josh Boyce didn't wow anyone in organized team activities, but it's dangerous to evaluate anyone in shorts. Dobson and Boyce opened camp healthy. Longtime Patriots receiver Julian Edelman is a candidate to make a huge leap in production, if he can get on the field.
At tight end, Daniel Fells has a better chance to step up than Jake Ballard or Michael Hoomanawanui. The Patriots are the best team in the league at adapting -- they'll rely on their running game more than ever. Shane Vereen can line up wide. This is going to take more than one player.
New York Jets: When will Santonio Holmes be ready?
Losing Holmes last season was perhaps more devastating for the Jets' offense than losing Darrelle Revis was for the Jets' defense. All the attention will be on the quarterback battle between Geno Smith and Mark Sanchez, and we'll be writing about that one plenty. But does it really matter who is starting at quarterback if he has no one to throw to?
Holmes is making more than $7 million this season, even after taking a paycut. That's the price you pay a premier wide receiver. But he's coming off a very serious Lisfranc foot surgery, and his readiness for the season is very much in doubt. Holmes said Friday he wasn't even sure if he would be able to play this season, which should send a chill up the collective spine of Jets fans. This could turn into a long-term source of drama for the team. Holmes needs to lead a receiver group that lacks a quality tight end and has no depth at wideout behind second-year pro Stephen Hill and Jeremy Kerley. Asking Holmes to lead always is a dangerous proposition.
Follow Gregg Rosenthal on Twitter @greggrosenthal.