This brief interview is full of information: http://www.hokiesports.com/football/recaps/20150323aaa.html.
"I'm anxious to see some young kids step up and play, particularly up front. A guy like Melvin Keihn, I'm anxious to see him. With Ken being out, Melvin and Seth Dooley are going to get a lot of reps, and they need a lot of reps. Those are kids that we are excited about. We want to see what Vinny Mihota can bring to the table, and we're excited about Yosh Nijman.
Emphasis is my own there, but I wonder if Foster means at end. It certainly seems ambiguous (at least to me).
In Bitter's interview Foster mentioned Ronny Vandyke and Holland Fisher would be at whip, but it seems like Adonis Alexander will get a look too.
Q: Brandon Facyson and Kendall Fuller are essentially out for this spring while rehabbing injuries. With that said, who are some young corners to watch this spring?
BF: "We're going to start Donovan Riley at rover and get him work at corner. He needs to continue to develop and grow and improve.
"As for those young corners, I'm looking forward to seeing how some of these guys compete. Greg Stroman really came on toward the end of the year. With Kendall being out, he's going to get a lot of reps. You've got Shawn Payne and Terrell Edmunds, and those guys are going to get a lot of work.
That's the first I've heard about Riley at rover.

Comments
echo
Donovan Riley at rover.... really? Riley has some strengths, but tackling wasn't one of them.
could he be using spring to cross-train players/get reps that way if we do get some injuries its not a ohh sheiittt we're screwed.
Correct me if I'm wrong but doesn't Rover need to be able to cover space and tackle well, maybe he's quick enough so he can work on tackling?
EDIT- Looked in search Bar and going over the positions/descriptions and wonderful insight on Bud Foster's D!
Riley seems like the Anti-CJ Reavis, the guy I hope wins that spot.
That's great to see Shawn Payne mentioned. I will be pulling for him throughout his career at tech. IIRC he was the one who called his mom crying when he got the offer and committed on the spot. He said tech was his dream school
I really hope Joe is right about Mihota back at DE. I think he will get lost in the depth at DT. He may or may not have the speed at DE but I think at least he will see the field there and be able to contribute. And who knows, perhaps in a game situation he will be much more effective than what can be seen in practice. That's happened many times before, Darren Evans immediately comes to mind.