Dolphins quarterback Ryan Tannehill reinjures left knee during practice

Miami Dolphins quarterback Ryan Tannehill reinjured his left knee in practice Thursday when it buckled as he scrambled and fell without being hit.

Tannehill walked slowly off the field accompanied by trainers, and there was no immediate word on the severity of the injury.

“You see your quarterback go down, you think the worst,” tight end MarQueis Gray said. “He’s in all of our prayers, and we hope he’s back on the field.”

Tannehill missed last season’s final four games, including a playoff loss at Pittsburgh, after spraining two ligaments in his left knee. He decided against surgery and took part in all off-season drills.

He was wearing a brace when his knee seemed to give out near the right sideline while running full speed to escape tackle Ndamukong Suh. Tannehill stayed on the ground at least 15 seconds surrounded by teammates before rising and leaving the field.

“I saw him buckle and go down. There was no contact on the play,” offensive coordinator Clyde Christensen said. “The initial reaction is, `OK, next man up.’ That’s football. It’s going to happen somewhere in this season. The game doesn’t stop. You go on to the next play. And then obviously my personal thing is, `Boy, I sure hope it isn’t serious.“’

The injury occurred during the seventh practice of training camp.

Matt Moore, an 11th-year veteran, went 2-2 as a starter replacing Tannehill last year and remains the backup.

“There’s a reason we have Matt Moore here,” Christensen said. “We hope he never has to play, and if he does he’ll be ready.”