Marcus Mariota Inactive vs. Dolphins with Hamstring Injury; Matt Cassel to Start

Matt Cassel will start for the Tennessee Titans on Sunday as quarterback Marcus Mariota is inactive due to a hamstring injury, the team announced.

ESPN's Adam Schefter first reported Mariota was not expected to play.

NFL Network's Ian Rapoport, citing a source, reported "Mariota's recovery time from the time of the injury was 2-4 weeks."

Mariota hasn't missed many games in two-plus-year career (five), but he has already had to deal with a few injuries. A broken fibula led to an early end to his 2016, while the hamstring issue is one of the first real nagging soft-tissue injuries he's nursed.

When healthy, the 23-year-old has proved to be one of the top young quarterbacks in the NFL. He is an accurate passer and athletic runner who can pick up large chunks of yards in a variety of ways.

So far this season, Mariota has completed 60 percent of his passes for 792 yards, three touchdowns and three interceptions. He's also logged 20 carries for 116 yards and three scores.

Veteran Matt Cassel will be the next man up under center so long as Mariota is out. The 35-year-old has played only sparingly in two years with Tennessee, his sixth organization in 13 years in the league.

While a strong offensive line and solid run game will help the offense move even without Mariota, there will be a significant downgrade with the starter unavailable.