Ryan Tannehill is expected to return to Miami in 2018 as the team’s likely starter. (Joe Skipper/Getty Images)

Ryan Tannehill has decided to undergo surgery to repair the torn anterior cruciate ligament in his left knee, according to multiple reports Friday. That effectively ends the season for the Dolphins quarterback, leaving recent addition Jay Cutler as Miami’s likely starter for 2017.

Tannehill, 29, had been mulling how to deal with the injury since he suffered it in a training-camp practice last week. He originally hurt his knee in a December game, missing the Dolphins’ final three regular season contests and a playoff loss to the Steelers, then opted to treat his partially torn ligament with stem-cell therapy and a course of rehabilitation.

That decision, made in consultation with the Dolphins and medical advisers, appeared to prove costly last week when Tannehill went down, untouched, while running toward the sideline. Miami moved quickly to address its quarterback situation, handing Cutler, 34, a one-year, $10 million contract.

Cutler, who had been released by the Bears in March and found little interest in the free agent market, had begun to pursue a career as an analyst on Fox football telecasts, but he had an out clause should an NFL job arise. With the Dolphins, he’ll be reunited with Adam Gase, Miami’s head coach who helped Cutler to his most efficient season while serving as Chicago’s offensive coordinator in 2015.

The Dolphins also have Matt Moore, who started the four games last season in Tannehill’s absence and who started 12 games for Miami in 2011, becoming a backup when Tannehill arrived the following season. Brandon Doughty and David Fales are further down the Dolphins’ quarterback depth chart.

The eighth overall pick in the 2012 draft out of Texas A&M, Tannehill had started every game, 77 in all, until December’s injury. As with Cutler, Tannehill had enjoyed his best season under the tutelage of Gase, who was hired by Miami last year.

In 2016, Tannehill notched career highs in completion percentage (67.1), touchdown percentage (4.9), yards per attempt (7.7) and passer rating (93.5), as he helped the Dolphins to a 10-6 record, its best mark since he was drafted.

Miami expects Tannehill to return in 2018 and compete for, if not immediately reassume, its starting quarterback job. He is signed through 2020 at annual salaries of less than $20 million, a reasonable rate for an NFL starter at his position.

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