Who was a backup this year but will be ready to start next year?

Keeping in mind that the school has to cut the number of kids on the team. So not only do they lose the normal number of seniors who are leaving, they currently have 122 kids on the team, and will need to cut that number to 105 before next season. They could carry some kids over into spring camp (technically they could carry some to fall camp) - but the reality is that unless they lose a lot of kids, or cut a lot of kids, there isn't exactly a ton of room for new players.

We've seen some leaving - but not enough to make those numbers.

Yeah - it would be good to supplement the OL and DL, but the truth is that there isn't a ton or room on the roster - depending on who is coming back next year from the current team, returning RMs, and new HS recruits.