USF coach Skip Holtz continues to make optimal use of his 105-man roster, and with receiver Colby Erskin suffering a season-ending knee injury Saturday, the Bulls have added former walk-on Justin Wilkins, who was on the roster in 2008, to the roster.

Wilkins, a junior who went to high school not far from Vero Beach at Fort Pierce Central, wore No. 86 at practice Tuesday night, but needs to go through the required five-day acclimatization process -- Holtz likes to call it that -- where he starts in shorts, then slowly works his way into full contact. Wilkins had shown promise in 2008 before he suffered a shoulder injury -- we wrote about him joining the team in 2008, and the strange part of it was that Wilkins originally was added to the Bulls roster in '08 after ... a Colby Erskin torn ACL.

GLASS HALF FULL?: Holtz said his excitement at big plays in preseason is mitigated by the realization that any big play by his team is also ultimately a big play against his team.

"Any time there's a big play, I get excited, go 'Ooh, nice play,'" he said. "Then you go, 'Ooh, that's our defense.' Then all the sudden, I'll see (Ryne) Giddins come off the edge, or (Craig) Marshall or (David) Bedford make a sack, and I'll go, 'Ooh, nice move on the tackle ... that's our tackle.' It's hard."

INJURY UPDATE: Tackle Jake Sims and tight end Jeff Hawkins were held out for a second day to guard against concussion-like symptoms. Defensive tackle Todd Chandler (hamstring) and running back Dontae Aycock (knee) also were held out with minor injuries.