Tannehill wore a brace on his left knee throughout offseason workouts and during training camp, and was planning to wear it all through the 2017 season.
NFL Network's Aditi Kinkhabwala initially provided some optimism for Tannehill and the Dolphins when she reported there was no structural damage to the knee. Last season, the quarterback suffered a partial ACL tear on that same knee but he opted for stem cell treatment instead of undergoing surgery. It was reinjured August 3, on a noncontact play, when Tannehill crumbled to the ground while scrambling in practice.
Miami went out and signed Jay Cutler to take over behind center, after Tannehill went down with the injury.
This is the first major surgery for Tannehill's, and it comes at a time when it seemed he was poised to have the best season of his career. While the Dolphins won't challenge the Patriots for the AFC East crown, they're improved roster gives them a chance to make their second straight playoff appearance if Cutler returns to form. According to Armando Salguero, the decision was reached after Dolphins coach Adam Gase and Tannehill were presented with several options.
Cutler, 34, started 15 games in 2015 with Gase as his offensive coordinator, throwing for 3,659 yards with 21 touchdowns and 11 interceptions.