It is early and things will likely change but right now I'd have to put it close to this:
Selvie moves to the weakside (Right DE), and if we can't get anyone else, will probably start there. If we draft (for instance) Barr or sign Allen, then Selvie is the backup on the weakside, which is ideal for that position. I like Selvie and he would be really stout against the run for a WDE, but I would like to have him coming in as the second guy in a rotation there. He would be a very strong rotational guy but only average as a starter. Selvie really was a terrific find for us and is better than a lot of people think, even though I do want him rotating in instead of starting. The guy is strong and has a knack for rushing the QB. He is a lot better than the unheralded free agent that many think of him as. Finding Selvie is worth all the crap we went through on the DL last year. It will start to pay dividends this season as we start to put better people around him.
At Strongside DE (Left DE) if we stick with what we have, I think Crawford and Bass are the rotational guys there. Either could start at this point and I think they will, at worst, be solid there. I think we might end up with a second or third round player that could play at SDE (perhaps Crighton or someone like him), which would be better, but Crawford/Bass would be ok if they stay healthy. I also think either one of them might end up playing some DT in certain situations. I completely trust Marinelli and if he thinks one or both should get some snaps inside, I'm fine with that.
We already have Melton inside and Terrell McClain is an athletic tackle that will be a useful rotational guy there. I expect at least one relatively early (1-3 round) draft pick at DT that will go along with those two guys and Hayden who is a stout plugger who will be fine in a rotation.
Overall, I'm expecting improvement by leaps-and-bounds along the DL and that is the engine that drives Marinelli's defense. With this super strong draft, I'm really excited about how much the DL can improve over last year's group.