A college teammate of current Bills running back C.J. Spiller, Hairston is a 6'6", 323-pound wall-off blocker with ridiculously long arms and just enough athleticism to get by as a right tackle in the NFL. He also has the versatility to kick into guard should the need arise.
Hairston was a three-year starter at left tackle for Clemson, and plays with a nasty streak - he'll get to the second level and bury guys. He's got a weird, fleshy body type, however, and doesn't have a lot of power in his base because of it. Though his natural length will help against speed rushers, he will still struggle with them. Technically, there is progress that needs to be made, as well, as he'll need to work on his pass sets specifically.
Long-term, Hairston has a chance to be a starting right tackle in the NFL, and I'm sure the Bills will be anxious to chisel this guy's frame out a bit more. He won't contribute much as a rookie, in all likelihood, but is heady and tenacious enough to be a valuable reserve right out of the gate.