NASHVILLE, Tenn. —Titans quarterback Marcus Mariota's 2015 season is over.
Interim coach Mike Mularkey made the announcement after practice on Wednesday at Saint Thomas Sports Park.
Second-year quarterback Zach Mettenberger will start Sunday's season finale against the Colts.
Mariota injured his right knee during the second quarter of the team's December 20 game against the Patriots when he was sacked by linebacker Jamie Collins.
Mettenberger replaced Mariota on the next series, and finished the 33-16 loss to the Patriots. Mettenberger also started for the Titans in Sunday's 34-6 loss to the Texans.
Earlier in the week, Mularkey said Mariota did some drop backs, but he indicated the Titans wouldn't play him unless he was 100 percent. The Titans ultimately decided the best route would be to hold Mariota out of the finale. He did not practice on Wednesday with the team after doing some light work in front of trainers and coaches earlier in the week.
Alex Tanney will be the No.2 quarterback behind Mettenberger on Sunday.
Mariota's final stats during the 12 starts in his rookie season: 230-of-370 (62.2%) for 2,818 yards, with 19 touchdowns and 10 interceptions. His final passer rating: 91.5.
Mariota, the second overall pick of the NFL Draft, broke several franchise rookie records, including most touchdowns (19), completions (230), passing yards (2,818) and passing attempts (370). Mariota completed three or more touchdown passes on four different occasions during his rookie season. He joined Peyton Manning (four in 1998) as the only rookie to accomplish the feat.
Mariota missed two games earlier this season after suffering an MCL sprain in his left knee in the team's October 18 game against the Dolphins.
Mettenberger, a sixth-round pick from LSU in 2014, will make his 10th career start against the Colts, and his fourth start this season.
On the season, Mettenberger has completed 96-of-153 passes (62.7%) for 897 yards, with four touchdowns and six interceptions.