Sunday started with a harsh look at the present and soon segued into a possible look at the future at a key offensive position. Offensive left tackle Jake Long might have played his last snap for the Dolphins.

After two tough series, Long left the game in the first quarter with what was announced as a left triceps injury. There will be an MRI today. Two players and a Dolphins staffer told The Miami Herald a torn tricep is the early diagnosis.

Rookie Jonathan Martin, who played left tackled for four years at Stanford before making the switch to right tackle with the Dolphins, moved back to left tackle for the remainder of the game. Utility lineman Nate Garner took Martin’s normal spot.

“I think I did all right,” Martin said. “I gave up that one sack late. I’m a little rusty. I haven’t played [left tackle] in a while. I’ll get some reps this week in practice and be all set.”

Center Mike Pouncey said, “John Martin did a great job. That’s his position from college. He’s very comfortable at that position. I think he’s going to do a good job if Jake can’t return.”

Long didn’t return despite ice on the arm for a few series and was out of uniform when the Dolphins returned for the second half. He went for X-rays after the game while Dolphins coach Joe Philbin told the media he gave no consideration to Long returning.

Considering Long played the last seven games of the 2010 season with a shoulder harness, that indicates this injury is more toward a torn muscle than a pulled muscle. And, with four games left in the 5-7 Dolphins season, that would mean Long’s season is over.

As could be Long’s Dolphins career. Long is in the last year of the contract he signed as 2008’s No. 1 overall NFL draft pick, which pays him an $11.2 million base salary this year.

The Dolphins could slap the franchise tag on him for a one-year deal. A longer deal becomes less likely if this is a triceps tear. It would be the third year he has been affected by injuries. In addition to the 2010 shoulder problem, he missed a game in 2011 with a back injury that ended his streak of 61 consecutive starts and the season finale with an arm injury.

Also, Long’s play no longer stands out as unassailable as it did earlier in his career.

On the first third down of the game, in pass protection, the 6-7, 320-pound Long got tossed aside like an annoyance by 6-2, 260-pound New England linebacker Rob Ninkovich. The following Dolphins’ possession opened with a Reggie Bush run for a loss of 3 on which Long appeared to blatantly false start. On second and 13, Ninkovich bull rushed Long backwards enough to force Tannehill from the pocket.

“He’s been a good player for a long time and he’s the leader on the offense,” Tannehill said of Long. “So, it’s tough to replace him. I feel like Nate Garner and moving Jonathan over the other side, they did a good job.”

Miami Herald sports writer Armando Salguero contributed to this report.