Los Angeles Chargers running back Melvin Gordon may not be able to make it back for Thursday night’s big matchup against the Kansas City Chiefs.

According to Adam Schefter of ESPN, it will be “challenging” for Gordon to play in the big division showdown as he continues to deal with a knee sprain.

Chargers initially were told the knee injury that Melvin Gordon suffered Nov. 25 was a 2-4 week injury. It’s now 18 days, and while the Chargers won’t make a final determination on Gordon until pregame warmups, it will be challenging for him to play tonight.

Gordon suffered the sprain on Nov. 25 against the Arizona Cardinals and has missed the last two games as a result. His backup, Austin Ekeler, has already been ruled out of the game. But the Chargers won’t make their final decision on Gordon’s availability until pregame.

On the other side, the Chiefs are also short at running back. Kareem Hunt is obviously gone, and Spencer Ware is doubtful to play. Damien Williams would step in to start if Ware can’t go.

As for the Chargers, rookie Justin Jackson would get his first-ever start if Gordon doesn’t get the green light. Jackson has come up with some strong performances recently. He put up 120 yards rushing on just 15 carries in Weeks 12 and 13. However, he was limited to just 12 yards on seven carries on Sunday against the Bengals.