L.C., I think you are right. I wasn't thinking about the return man. Given the tackling style shown, it looked more like an offensive player. However, #51 appeared to be playing two hand tag on the play (and I think he missed that too).
51 was Jovon Johnson. Here's
the full play. In my mind the blame goes to the DE on the far side (which I'm sure he was told to do - but, who has contain???). He circles around inside, and is totally out of the play. Jovon Johnson was the 2d guy in at the top. He gets blocked, but hustles back to try to stop Terhune. He just took a bad angle. Had Terhune even had to pause a little from hurdling Daz, the angle would have been right, but since he didn't even slow down going over Daz, Johnson ended up missing behind him. You can see early in the play Carpenter is 5 yards behind Terhune. With 55 yards to go, in this version you can see Carpenter is only 5 yards behind Terhune, and in the second angle you can see him slow up, before accelerating again. I see Devin Jones running hard and closing a lot of ground from clear on the far side, and Aaron Macer in the picture as well.