The Oakland Raiders announced Monday they have placed running back Marshawn Lynch on injured reserve.

Tom Pelissero of NFL Network first reported the news.

Lynch was initially expected to miss at least a month with the groin injury, but the Raiders clearly believe the injury will take much longer to heal.

While he will be eligible to return this season, the Raiders won't be able to activate him until Christmas Eve, according to Vic Tafur of The Athletic.

The 32-year-old got off to a hot start to the season with a touchdown in each of his first three games followed by a 130-yard effort in Week 4. However, he slowed down over the past two weeks with 76 total rushing yards on 22 carries, both Raiders losses.

For the season, Lynch has 376 rushing yards and three touchdowns, plus 84 receiving yards. Meanwhile, the Raiders are just 1-5 and look like they will compete for the No. 1 overall draft pick.

Veteran Doug Martin will likely handle much of the early-down work in the backfield, while Jalen Richard will try to become a bigger factor after being used mostly as a receiver to start the season.

Lynch spent a year in retirement before coming back to join the Raiders last season. He totaled 891 yards and seven touchdowns for his hometown team, starting all 15 games he played.

He might not want to return to the Raiders next year, and the pending free agent likely won't find too much of a market with his age and the mileage on his body.

If he doesn't return this year, it could be the end of the line for the five-time Pro Bowler.