There's been some discussion on this site about our TEs being essentially interchangeable with FBs. I've never completely bought that argument, since I see FB as a distinct position that requires a slightly different set of skills (and often a different body type) than TE. BB was asked about the difference between going with two TEs (and no FB) and going with one TE and one FB. Belichick's answer is quoted below and is a great example of BB at his best when explaining basic football. If you haven't read it already, read it now. It's great stuff. BB describes some of the strategic differences between the two-TE set and the two-back, one-TE set. I'd add that the FB isn't just a different position from TE with different strategic possibilities, but also a position that demands a slightly different type of player. While many TEs can do a lot of what FBs can do, FBs have to see the running play unfold in much the same way as a RB and need some of the same running skills as a RB (which often requires a more compact body type). TEs, meanwhile, need to be taller, more like linemen, and think more like WRs. So while you can get by with all TEs and no FB, if you are going to utilize a FB regularly, it's probably best to actually put a specialist FB on your roster. Does this mean there's a spot for Develin this year? Not sure, but it will be interesting to watch as cuts come.
Here's BB on the subject:
Q: On the idea of running on a two-back set compared to two tight ends with one tight end on each side of the line or two tight ends on the same side of the line, what does that give you as an offense when you have a two-back set in the running game versus two tight ends? Is that a different dimension that’s a positive or are they equal in terms of the benefit they give you?
BB: You’re talking about two backs and one tight end versus one-back and two tight ends?
BB: There are still two receivers in the game?
BB: Well, I think when you, just fundamentally, when you have one back in the backfield and you have four on-the-line receivers, that gives you an ability to get into the defense potentially with four people. Or even if it’s three of them, sometimes the defense isn’t sure which three of them it is. One tight end could be in it and the other guy could be in protection, that type of thing. I think you’re able to attack the defense from the line of scrimmage a little bit quicker and with a little less predictability, depending on who those players are, of course. That's certainly a factor. But as far as your running gaps, I mean, you can put more width at the formation by having a guy on the line, whether it’s four on one side and two on the other side of the center or three and three. You just have a wider front, which there are some advantages to that. By having them in the backfield, you can create that same four-man surface or three-man surface after the snap so the defense doesn’t know where the four-man surface or three-man surface is. The fullback has to – he can build that from the backfield. And then there are also, let’s say, a greater variety of blocking schemes with the fullback in the backfield because he can block different guys and come from different angles. He's not always behind the quarterback. He could be offset one way or the other and create different blocking schemes and angles that it’s harder to get from the line of scrimmage. Also, depending on who your tight end is, it can be a little bit easier to pass protect seven men because two of them are in the backfield instead of us having one in the backfield. And then when you start running guys up the middle in the gaps and things like that. I think fundamentally it’s a little easier to pick them up when you a have a guy in the backfield that can step up and block him from the fullback position as opposed to a tight end in the line of scrimmage who probably isn’t going to be able to loop back in and get him, so the line is probably all going to have to gap down or not gap down if the guy drops out and all that. It just creates a different – it creates some advantages, I think, and it also creates some things you have to deal with. You just have to decide how you want to deal with them. Obviously when you have a guy in the backfield, it’s harder to get those two receivers vertically into the defense in the passing game. They’re usually running shorter routes to the flat or checking over the ball or those kind of things, short crossing routes – versus having that fourth receiver on the line of scrimmage who can run some downfield routes, again depending on who the individual person is. The skill definitely changes what you can do with that guy. So, I mean, I think those are the things that come into play. Some teams are very settled in one type of offense or another, so all of their plays and their rules or their adjustments come from that particular set. And other teams use multiple looks to, say, run the same plays or the same concepts to try to give the defense a different look. It’s harder for them to zero in on what they’re doing. But they’re able to do similar things from different personnel groups or different formations. That's a long answer to a really short question, but I hopefully that helps a little bit.