Tennessee Titans quarterback Marcus Mariota's rookie season is over, interim coach Mike Mularkey confirmed Wednesday.
Mularkey said it was "not worth the risk" to have Mariota play in the season finale against the Indianapolis Colts due to his knee injury.
Mariota, the second overall pick in the 2015 NFL Draft, suffered a sprained MCL in the Titans' 33-16 Week 15 loss to the New England Patriots on Dec. 20. He sat out the 34-16 loss to the Houston Texans last Sunday.
Last week, Mularkey held out hope that Mariota might return for the season finale.
Mariota, 22, finished his season with a 3-9 record as a starter, missing four games due to a pair of knee injuries. He completed 230 of 370 passes for 2,818 yards, 19 touchdowns and 10 interceptions, posting a quarterback rating of 91.5. Mariota also rushed 34 times for 252 yards and two touchdowns, including scoring the go-ahead touchdown on an 87-yard run when the Titans beat the Jacksonville Jaguars 42-39 on Dec. 6 to snap the NFL's longest home skid at 11 games.
Second-year quarterback Zach Mettenberger, who has a 0-9 career record as a starter, will start Sunday's game against the Colts. Alex Tanney will be the No. 2 quarterback behind Mettenberger.
The Titans (3-12) are in position for the No. 1 overall spot in the 2016 NFL Draft, which they can secure with a loss.