For the first time in his legendary nine-year NFL career, Los Angeles Rams defensive tackle Aaron Donald will have to miss a game because of injury.

Per Greg Beacham of the Associated Press, Donald has officially been ruled out for Sunday's game against the Seattle Seahawks because of a sprained right ankle.

Donald suffered the injury in Los Angeles' Week 12 loss to the Kansas City Chiefs, which extended the team's losing skid to five games. Through 11 contests, the seven-time All-Pro selection has racked up 49 total tackles, five sacks, a forced fumble and a fumble recovery.

Since being drafted 13th in 2014, Donald has been a mainstay on the Rams defensive line. He's played 138 out of a possible 140 career games, only missing two in 2017—one while he was holding out for a new contract to begin the season and the other being the team's Week 17 game, as it had already secured a playoff berth.

Donald's injury is the latest bit of bad luck for the defending Super Bowl champions. The Rams are already without star wide receiver Cooper Kupp, who is on injured reserve after he underwent surgery for a high ankle sprain.

Starting quarterback Matthew Stafford has also missed time this season while dealing with concussion symptoms. Receiver Allen Robinson II has already been ruled out for the season with a stress fracture in his foot.

On Tuesday, Rams head coach Sean McVay told reporters that the team "has not ruled out" shutting down Donald, Kupp or Stafford for the remainder of the year. At 3-8, Los Angeles is unlikely to make the playoffs and would become the first defending Super Bowl champions to miss the postseason since the Denver Broncos in 2016.

In Week 13, the depleted Rams will face a Seahawks team that is looking to end a two-game slide and stay alive in the playoff race.