The Seattle Seahawks lost to the Los Angeles Rams by a score of 28-12 on Sunday, and they also lost a key contributor of their offense in the process.

According to Brady Henderson of ESPN, running back Rashaad Penny suffered what head coach Pete Carroll is calling a “significant” ACL injury that will keep him out for the rest of the season.

Penny sustained the injury on a 16-yard reception in the first quarter and exited the game.

The second-year back was just starting to get going, as he carried the ball 14 times for 129 yards and a touchdown in Week 12 and followed that up by rushing for 74 yards and a score off of 15 attempts in Week 13.

On the season overall, Penny totaled 370 yards and three touchdowns on the ground, averaging 5.7 yards per tote. He also logged eight catches for 83 yards and a score.

The 23-year-old, who played his collegiate football at San Diego State, was originally selected by the Seahawks in the first round (27th pick overall) of the 2018 NFL Draft.

Due to a breakout season from fellow halfback Chris Carson, Penny did not receive a ton of playing time during his rookie campaign, but when he was on the field, he was productive, registering 419 yards and a couple of touchdowns while recording 4.9 yards per carry.

Penny was expected to have a larger role in Seattle's offense this year, and while he had his moments early on, he did not really bust out until Week 12.

The Seahawks are now 10-3 on the season and fell out of first place in the NFC West with their loss to the Rams.