According to ESPN, the Dolphins are concerned Ryan Tannehill will need season-ending surgery.

The Dolphins are worried quarterback Ryan Tannehill may need season-ending knee surgery, Adam Schefter and Jeff Darlington of ESPN report.

Tannehill left practice with a non-contact left leg injury Thursday that according to ESPN had the team "concerned" initially. NFL.com reported there was no structural damage in the knee.

Tannehill was mid-scramble when he fell and landed uncomfortably, remaining on the ground while examined by training staff. Last year, Tannehill sprained his ACL and MCL in the same left knee. He wears a brace on that leg but did not need surgery.

Video of the play is below.

Miami has had a difficult week with key injuries, with starting running back Jay Ajayi currently in the concussion protocol.

Last season, Tannehill went 8–5 and threw for 2,995 yards and 19 touchdowns. He has been the team’s starter in every game of his five-year career, with a lifetime 62.7% completion percentage and 106 touchdowns to 66 interceptions. The team has gone 39–41 in that span.

Matt Moore is the Dolphins’ primary backup and went 2–2 in relief of Tannehill last season. The team won a wild card berth but lost to the Steelers in the first round of the playoffs.