CORTLAND, N.Y. -- New York Jets running back Joe McKnight appeared to be OK after he was carted to the locker room, wearing an oxygen mask, after dropping to the field during a drill Monday.
McKnight, who has a history of migraine headaches, has been recovering from a head injury and dealing with dehydration during training camp.
About an hour after being escorted to the locker room, he walked to the field to watch the end of practice in a T-shirt and shorts while wearing dark sunglasses. McKnight was not available to the media, walking past reporters without comment, and the Jets had no further details on his condition.
The Jets confirmed that while he was in the locker room being treated, McKnight angrily responded on Twitter to someone he thought was a reporter who wrote, "about time you get released. Good luck. And stay healthy."
McKnight tweeted about trying to keep his cool before adding "now it has gone too far with these reporters." He then asked, "are you outside," but a public relations staff member assured McKnight the critical tweet had not come from a reporter but a fan.
Heading to the field at the start of practice, he dropped to a knee three times and was examined by trainers. After pouring water over his head, McKnight then jogged and appeared OK.
"If the trainers thought he would be at risk, he would never be out there, ever," Jets coach Rex Ryan said.
Wearing a red no-contact jersey, he was participating in a drill 45 minutes into practice when he went down again after diving for a pass. Trainers rushed to him, and then walked him to a medical tent behind the field.
McKnight remained on his right side as he was examined for several minutes. It appeared trainers were also checking his lower left leg before he was removed on a cart. He was wearing an oxygen mask as he walked gingerly on his own into the locker room while a trainer held the tank.
"For whatever reason, he stopped or whatever and that's fine," Ryan said. "There's no chance any player would be on the field if the trainers or doctors felt that it wasn't safe for that person to be there."
McKnight has had a rough summer. He failed a conditioning test just before the team reported to Cortland, but passed the next day. He blamed the failure on dehydration and his low percentage of body fat (3.3 per cent). Ryan also suggested that McKnight has "anxiety" when it comes to the conditioning tests.
McKnight was arrested two weeks ago in New Jersey for outstanding traffic warrants. He was released on $320 bail, the amount of the tickets.
Later that week, he injured his head during practice -- an injury the Jets still haven't officially called a concussion -- and he returned to the field Sunday, wearing the no-contact jersey. After practice, McKnight spoke to reporters for three minutes, but refused to answer any questions about his head injury or the arrest, repeatedly saying, "I'm not getting into that right now."
McKnight, the team's fourth-round pick out of Southern California in 2010, has had his moments on the field with the Jets, but his inconsistency has kept him from being a bigger part of the offence. He has proven himself to be an outstanding kick returner, with two touchdowns, including a 107-yard score in 2011 that's the longest play in franchise history.
But his health issues possibly put him on the bubble for making the 53-man roster.
"We've got a long way to go before we make the final decisions and things," Ryan said. "But Joe has led the league in kick returns. He has plenty of talent, but durability, there is concern about durability."