Defensive line
Gone:
Jonathan Cooper and Tommy Togiai have declared. Togiai is the biggest hit because he was pretty strong and it doesn't feel like there is as strong a replacement on the roster. Cooper had a strong senior season which is nice to see after he battled injury for much of his career.
Unclear of the situation of Antwuan Jackson. He went through Senior Day and my assumption is anyone going through Senior Day isn't planning on coming back unless they say so, and he hasn't said so. But there looks to be a spot there for him if he wants to return. (Edit: he did return)
Back:
Defensive end is pretty loaded. Zach Harrison and Tyreke Smith come back as the clear cut starters, and they are a pretty daggum good pair. Backing them up is Javonte Jean-Baptiste and Tyler Friday, who are both experienced guys who would start for a lot of teams. They have always rotated in at least four guys, so expect that to continue. Behind them are youngsters Noah Potter and tight end convert Cormontae Hamilton. Also in the mix will be true freshman uber recruit Jack Sawyer, the fourth ranked recruit in the nation. As Woody Hayes said, "if you've got a big gun, use it" so expect to see him out there. They also have a shot at the 3rd ranked recruit, J.T. Tuimoloau.
Tackle is a little bit more unsure. The good news is they return Haskell Garrett, who survived a gunshot to the face to have a great season (Edit: I've read he was returning, but I've also read he's still thinking about it, needless to say, him leaving too would be a blow). Losing Togiai is a blow, though, and we'll see how they replace him. Taron Vincent is a former five star prospect who will hopefully develop into that ranking. Jerron Cage is an experienced DT who got plenty of run against Alabama when Togiai was out. Ty Hamilton seems to be the top guy of the rest, which includes Darrion Henry-Young, Jacolbe Cowan, and Jaden McKenzie.
They have a couple freshmen that might get some run. Mike Hall is a top 50 prospect, while Tyliek Williams is a mammoth out of Virginia who already looks like the biggest DT on the team.