FLORHAM PARK, N.J. — The New York Jets' wacky quarterback situation took yet another twist.

Greg McElroy has a concussion — which he didn't reveal until Thursday — and will be replaced by Mark Sanchez as the New York Jets' starting quarterback in the season finale at Buffalo on Sunday.

Coach Rex Ryan walked into his news conference before practice, took the podium and opened with: "You're not going to believe this."

McElroy, preparing to make his second NFL start in place of the benched Sanchez, was lifting weights Thursday morning and started experiencing headaches, Ryan said. McElroy went to the team's training staff and then revealed he was suffering concussion-like symptoms after being sacked 11 times in the Jets' 27-17 loss to San Diego last Sunday.

McElroy and head trainer John Mellody then went to Ryan to tell the coach the news. Ryan was not certain exactly when McElroy suffered the concussion.

"We come to find out that Greg wasn't exactly truthful with our training staff after the game," said Ryan, who acknowledged he was "stunned" to hear it. "He never disclosed that he had symptoms after the game to our trainers. Right now, he's being evaluated for a concussion."

Ryan said there was no way he would play McElroy against the Bills and the third-stringer will "definitely be out." McElroy had been listed on the injury report Wednesday with a mild abdominal strain, but was a full participant in practice and was expected to play without any issues.

"I admire his courage and everything else, but you have to be truthful and I think that's the lesson learned here with the medical staff," said Ryan, who added he would speak to the entire team about concussions after practice. "The fact he really wanted to play, I understand the competitive side of Greg and all that, but the most important thing is the health of the players.

"Obviously, I feel fortunate that something like this showed up without him going out there and putting himself in harm's way."

Ryan chose to start Sanchez over Tim Tebow because the team has just two practices and a walkthrough to prepare before the game.

"Mark has had success earlier in the season against Buffalo and he's very familiar with them," Ryan said. "That's the reason I'm going with Mark."

Sanchez appeared to be on his way to a solid season when he threw three touchdown passes in the Jets' season-opening 48-28 win over the Bills. It ended up being his best game of a lousy season. Sanchez was benched for the first time in his four-year career after turning the ball over five times at Tennessee on Dec. 17. McElroy leapfrogged Tebow on the depth chart to start against the Chargers.

"I know he believes in himself," Ryan said of Sanchez, "and any competitor would want this opportunity."

After finding out about McElroy's condition, Ryan spoke with both Sanchez and Tebow to tell them of his decision.

"Obviously, Tim's not happy with that, as you'd expect," Ryan said.

The news comes on the heels of some tension between Ryan and Tebow last week, when the popular backup quarterback told the coach he was "disappointed" at not getting the start and wanted to play "regular quarterback." ESPN New York first reported Sunday that Tebow asked out of the wildcat, and a person with knowledge of the situation confirmed that to The Associated Press. The two met again last Friday to clear the air, and Tebow reiterated that he was willing to do anything the team asked him to do.

Tebow insisted Wednesday that he did not refuse to do anything and acknowledged that Ryan might have misinterpreted what he said.

"It was just me asking to get an opportunity to play the position I love, which is quarterback," Tebow said. "It wasn't me asking out of anything."

Ryan said he understands that Tebow is frustrated at the situation and by not starting, but again would not disclose anything that was said between the two in their conversations last week.

Tebow will be the No. 2 quarterback on Sunday at Buffalo, and could play — but it won't be as the starter.

"Obviously, he'd like a shot at it," Ryan said, "but with the situation the way it is, it's a short window, really, to get the preparation time in and I just think it's best for our football team."

With the way the season has played out, from the quarterback controversies to the injuries suffered by key players, Ryan was asked if this is the strangest year he has ever experienced in the NFL.

"Yeah, I would say that's pretty accurate," Ryan said, laughing. "And, we've had some strange ones."