9/8/2013 Bills 21 Patriots 20. 8:50 remaining in the 4th quarter, 3rd and 1 at BUF 49. Johnson drops 1st down and likely would have gotten close to FG range with a catch.
11/27/11 Jets 28 Bills 24. 0:35 remaining in the 4th quarter, 2nd and 13 at NYJ 47. Johnson drops 1st down at the 25 and would have likely scored a GW TD with a catch.
10/2/11 Bills 20 Bengals 13. 8:30 remaining in the 4th quarter, 3rd and 1 at the BUF 47. Johnson drops 1st down at the CIN 47. With catch, Buffalo moves close to FG range which would have made it a two score game. (To be fair, this was likely a blown call, cleaner catch leaves no doubt though.)
11/28/10 Bills 16 Steelers 16. 10:30 remaining it OT, 1st and 10 at the PIT 40. Johnson drops GW TD in the end zone. With catch, Buffalo wins in OT.
4 late game drops that had a pretty big effect swinging wins to losses.