The San Francisco 49ers announced Saturday that rookie running back Trey Sermon has been placed on injured reserve with an ankle ailment.
Sermon will now miss at least the next three games and won't be eligible to return until a Dec. 23 matchup against the Tennessee Titans. The 22-year-old suffered the ankle injury in the 49ers' Week 12 win over the Minnesota Vikings.
Sermon has mostly played as a special teamer this year. The third-rounder out of Ohio State has just 41 carries for 167 yards and one touchdown in nine games. He also has three catches for 26 yards.
Sermon plays behind Elijah Mitchell and Jeff Wilson Jr. Head coach Kyle Shanahan explained to reporters in November why that's the case:
"Trey had an opportunity when guys got hurt and I thought he got better in each game with that. But he didn't do enough for us to put him ahead of Elijah or Jeff. And so it's pretty much as simple as that, like if Jeff wasn't out there or Elijah wasn't, he would have taken one of those roles.
"When it came to third downs, we always started out with [RB] Raheem [Mostert] then it went to Hasty. And now we've gone with Juice. Not always wanting to put a rookie in a third-down role, so he had an opportunity when there was injuries, but those guys have come back and we still have those guys ahead of him."
Mitchell has been San Francisco's most effective running back this season, rushing for 693 yards and four touchdowns on 143 carries in eight games. He also has 14 catches for 108 yards.
Wide receiver Deebo Samuel has also been more involved than Sermon on the ground, rushing for 203 yards and five scores on 25 carries in 11 games.
The 49ers enter Sunday's game against the Seattle Seahawks with a 6-5 record. The loss of Sermon likely won't have much of an impact on the team's offense.