McKnight arrived in San Francisco on Wednesday night and was cleared to practice with the team, but his status for Saturday's Emerald Bowl matchup with the Boston College Eagles is still uncertain.
"Now that the part of it Joe could contribute is completed, we made it clear how much we wanted him to get here and get with us," Carroll said. "There are still other things that need to be done; there is still other processing that needs to be taken care of. And we don't know when that's going to happen."
While McKnight still has to be cleared to participate in the final game of the season, Carroll said there is a real chance that the elusive tailback could be available Saturday.
"The fact that they got this far along allows us to think that there is a legitimate chance for him to be OK'd to play," Carroll said.
Whether or not McKnight is cleared in time to play against Boston College remains to be seen, but Carroll appeared optimistic that he will ultimately be cleared of any wrongdoing.
"We really think he's going to be OK, but it might happen after the game, which would be a real misfortune if that's what takes place," Carroll said.
McKnight has only missed two days of practice, so he is familiar with the game plan. Carroll said he is concerned that the ordeal could be mentally draining for the junior from Louisiana.
"It's been a very difficult week for him and on him… He's happy to be here but worn, understandably," Carroll said. "All of this has been challenging for Joe."
- USC senior cornerback Kevin Thomas remained limited on Thursday with a sore ankle. Thomas is expected to play in the Emerald Bowl.
"His ankle's still a little sore. We just felt on this turf, we should take another day," Carroll said. "It's come up from pounding on it. It's not so much of a sprain as it is jamming it. He could've practiced today and he could've made it through practice today, but we don't know what the result would've been."
- With extra time to prepare for Boston College, Carroll said he is hoping that freshman quarterback Matt Barkley will display a strong command of the game plan.
"We've worked very hard at this game plan. We want to see him be efficient and utilize it. We're very strict with what we're doing in this game plan," Carroll said. "We're happy with what we put together and with what we're asking him to do and the whole offense. I'm anxious to see if we can execute really well and be on rhythm, protect him and get the ball out.
"This is a two-week preparation for him. He should be at his best. This is the culmination of the season. He had a little break and came back from it. It's almost like going into a mini spring football. I'm hoping that he feels very comfortable with what's going on and that he can show that he's growing."
- With all the commotion surrounding McKnight's eligibility issues it would be easy for the players to be distracted, but Carroll said he hasn't noticed that during the Trojans' preparation.
"More than anything, it just feels like the guys are injured in the regard that they're not available to you," he said. "Remember, we have a language and mentality when we lose guys that really resets us to look ahead as opposed to looking back. I think we've been disciplined about that. It hasn't come up; it hasn't been an issue at all. I don't think it's a factor."
Cornerback Kevin Thomas remained limited with a sore ankle.
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