Here is a list of a few defensive prospects that Michigan are in good shape with:
Cullen Christian, (Pittsburgh, PA) - Rated #3 corner in the nation, 4 star prospect. Has had Michigan as his leader for a while, although unlikely to commit soon, he plans to take some visits.
Brandon Ifill, (Pittsburgh, PA) - Rated #18 safety in the nation, 4 star prospect. Teammate of Cullen Christian, if one of them commits, lets hope the other follows. Has a top two of Michigan and Maryland, with no outright leader.
Tony Grimes, (Hollywood, FL) - Rated #5 corner in the nation, 4 star prospect. Very physical player, has Michigan as a leader, although he will be visiting some big SEC schools, such as Georgia and Florida. Won't be committing anytime soon.
Rashad Knight, (Jacksonville, FL) - Rated #71 corner in the nation, 3 star prospect. Very underated here, likely to move up the rankings after his senior season. Has Michigan as his leader.
These are recruits that Michigan has a very strong chance of signing, but I wouldn't expect any of them to commit soon!
Ratings from scout.com