The Jets quarterback carousel took another unexpected spin Thursday.
The team discovered starting quarterback Greg McElroy had suffered a concussion in Sunday's loss to the Chargers after he experienced headaches while lifting weights Thursday morning.
Jets coach Rex Ryan said McElroy won't play Sunday against the Bills and Mark Sanchez, who McElroy replaced last week as the starter, is back in as the starting quarterback.
Ryan picked Sanchez over Tim Tebow, who has not started a game for the Jets.
"I'm going to start Mark Sanchez," Ryan said. "The reason I'm starting Mark is we have two practices and one walkthrough to get ready for Buffalo. Mark has had success earlier in the season against Buffalo. He's very familiar with them. That's the reason I'm going with Mark."