Barring an unlikely turn of events, the Colts will play their final game of the season on January 3, when they take on the Tennessee Titans at Lucas Oil Stadium. In that game, they might be facing the Titans' backup quarterback instead of rookie franchise signal-caller Marcus Mariota.
Mariota suffered a knee sprain during Sunday's loss to the Patriots that will keep him out for this week's game against the Texans, and while Titans coach Mike Mularkey said on Monday that the team is still hopeful Mariota could play in the regular season finale, it's no guarantee. According to ESPN's Chris Mortensen, Mariota is out for the rest of the season (the final two weeks) with an MCL sprain, which would mean that he would miss the final game against the Colts.
If that's the case, the Colts surely won't be complaining. In his rookie season, Mariota has impressed and has stacked up a nice case for the Offensive Rookie of the Year Award. He has started 12 games and completed 230 of 370 passes (62.2%) for 2,818 yards (7.62 yards per attempt), 19 touchdowns, and 10 interceptions for a passer rating of 91.5, and he has also added 252 yards and two touchdowns rushing (while averaging 7.4 yards per attempt) and caught a 41 yard touchdown pass. Earlier this year against the Colts, Mariota completed 27 of 44 passes (61.4%) for 367 yards (8.34 yards per attempt) and two touchdowns with two picks for an 84.2 passer rating, and he almost led his team to a victory, falling just short in a 35-33 loss.
In his place it would be second-year man Zach Mettenberger getting the start, who in 12 career games (all with the Titans) has completed 62.6% of his passes for 2,075 yards and 11 touchdowns with 12 picks. It's possible that the Colts could still be without their franchise quarterback as well, as Andrew Luck will not play this weekend and his status is currently unknown for the regular season finale.
The injury to Mariota could have bigger implications for the Colts than simply that regular season finale, however. The Titans will host the Texans on Sunday, and the Colts really need Houston to lose in order to keep realistic playoff hopes alive. Tennessee has struggled this year, going just 3-11, and without Mariota it will be an even tougher test to knock off the current AFC South leaders. A Texans win on Sunday would diminish the Colts' playoff hopes even more, and Houston will be facing a Titans team without their franchise quarterback.