FLORHAM PARK, N.J. -- New York Jets running back Joe McKnight has been dealing with nerves and a stomach flu, and he isn't in ideal shape at rookie minicamp.

"It's not a conditioning situation, but I wasn't in the best shape," McKnight said after the afternoon practice Saturday. "I'm not in good shape right now. I mean, I'm in OK shape, but I'm not in the best. I could be better."

McKnight, the Jets' fourth-round draft pick out of USC, wants to stay around the training facility after minicamp ends Sunday so he can get back in shape.

"I just want to prove myself to everyone everyday," he said. "I just want to come out and prove myself and just show them that I'm willing to do anything."

McKnight has endured a rough first two days of camp, vomiting on the field and having both calves cramp up in his first practice Friday.

"It was certain nerves and my stomach wasn't right, and the nerves were just part of it and they weren't the whole part," he said. "I was a little sick when I came out, but that's no excuse."

McKnight was doubled over again, a wet towel around his neck, in the morning session Saturday while dealing with hydration issues. He was able to control his stomach this time, though.

"Today's practice was good, better than yesterday's," McKnight said. "I made it through OK. I didn't give it up today."

McKnight also has had some problems with drops on passes out of the backfield, but Jets coach Rex Ryan said the rookie has been impressive running with the football.

"He's making one mistake after another and then you put the ball in his hands and he looks pretty good," Ryan said. "Just go right, Joe. He's fighting through it."

McKnight said running backs coach Anthony Lynn has talked to him about improving the way he handles himself.

"Just being a pro," McKnight said. "That's basically what he's told me everyday. He didn't like the way I was throwing up and everything. Professionals don't do that."

The Jets traded two picks to the Carolina Panthers to move up last Saturday so they could take McKnight. His presence made Leon Washington, a player with a similar skills set, expendable as the Jets dealt the former Pro Bowl kick returner to the Seattle Seahawks.

"I don't think we need to overreact with this," Ryan said. "He still does some great things out there."

Copyright 2010 by The Associated Press