In this sense, it's easier and quicker just to discuss those who can play OT.
Obviously, we have Cam Robinson at LT, but he probably has only two years left (early entree into the Draft), and he may be the only pure LT prospect on the roster right now. Grant Hill can probably play LT in a pinch, but is more suited to RT, and an illness wrecked his 2014 season, so he only has two seasons left unless a medical redshirt comes in (which is going to be close). Pierschbacher has more long-term potential at LT, but spent most of his redshirt season at RT. Regardless, that's basically the three-man rotation going into 2015-2016, and that's basically it.
Dominick Jackson remains an option at RT for 2015, and everyone is hoping that comes through, but he didn't make a big surge at a starting job this year and may not next year. Likewise, it's possible that he could end up at one of the OG spots, opposite Shank Taylor.
Moving into 2016 and beyond, it's relatively thin at OT. We've got a couple of solid options, but not a lot of depth, and most of the guys we are bringing in so far this season are more likely to end up playing inside. Matt Womack has a chance at playing RT due to the length of his frame, but he's going to have to showcase he has the foot speed and fluidity necessary to play outside with a 6'7, 330+ pound frame. A lot of people did think that Richie Pettitbon may get some looks at OT, but as time goes on I'm tending to doubt it. He's on the shorter side for an OT, and was a bit shaky at times in pass protection at the all-star game. If I had to say, I would probably peg him as an OG candidate.
So, in a nutshell, we need to add another OT in this class, if possible. It's not a dire need, but definitely could use another solid prospect at the spot. Either way, I figure it's a big target area for 2016.