DAVIE, Fla. (AP) — Ryan Tannehill sat in the team cafeteria Friday, his left leg in a brace and propped on a chair as he watched practice from afar with a sullen stare.

He has again been demoted to the role of spectator, perhaps for the entire season.

Knee surgery is an option for the Miami Dolphins quarterback, although it's possible an operation can be avoided, coach Adam Gase said. But even then Tannehill is expected to be sidelined at least six weeks.

Tannehill, who missed the final four games of last season with two sprained ligaments in his knee, reinjured it in practice Thursday. An MRI was inconclusive, and the Dolphins are consulting with a multitude of specialists.

"I wouldn't say second and third opinions — we're probably going deeper than that, talking to a lot of people, making sure we get the right information," Gase said. "Everything is on the table right now."

There's no timetable for a decision, he said.

Gase said he hasn't decided whether to bring in another quarterback. Matt Moore went 2-2 as a starter replacing Tannehill last year and becomes the new No. 1 — for the moment. The other QBs on the roster are David Fales and Brandon Doughty.

"Right now Matt is our quarterback," Gase said. "We'll see where we go from there. I've got to figure out what's going on with Ryan, and then we'll make decisions after that."

The Dolphins could pursue Colin Kaepernick, who parted ways with the San Francisco 49ers in March and remains unsigned. Jay Cutler, who played for the Chicago Bears when Gase was their offensive coordinator, would be an option if he's willing to give up his new job as a TV commentator.

The Dolphins spent several weeks after last season assessing the extent of Tannehill's ACL and MCL sprains before ruling out surgery. Tannehill instead rehabilitated the partially torn ligaments and underwent stem cell treatments.

He didn't miss an offseason workout, and by May was saying he felt 100 percent. But his knee buckled on a scramble Thursday, and he fell without being hit.

"Yesterday was a tough day," Gase said, "seeing how hard he worked to be back out there and go through the spring, and a lot of the things he did to make sure everything was good, and he felt great. It caught him off guard a little bit. Seeing him that way is tough."

Moore had a similar reaction, even though for him, Tannehill's injury means a chance to play.

"It stinks," Moore said. "As a buddy and teammate, you never want to see it happen. But this is part of my role, and I've done this before."

Moore has 28 starts in 10 seasons and played well subbing last year. He threw nine touchdowns with four interceptions in his four starts, and said the chance to play then will help now.

"It does a lot for confidence, especially at the quarterback position," Moore said. "I've gotten to play with a lot of these guys with live bullets. It's good."

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