Former Michigan State and current Pittsburgh Steelers running back Le’Veon Bell could miss a portion of the 2016 season.

And it isn’t because of his rehabilitated knee.

According to ESPN, Bell is facing a four-game suspension from the NFL for missing a drug test. Bell is not facing a suspension for a failed drug test, but he was suspended two games for a violation of the NFL’s substance abuse policy after he was arrested on charges of marijuana possession and DUI in the summer of 2014.

The appeals process is still in the works. As a result, a suspension hasn’t been issued yet.┬áIf Bell doesn’t win the appeal, he’ll be suspended for a quarter of the NFL season.

The former Spartan is entering a contract year and is still working his way back from season-ending knee surgery.

Bell has averaged an NFL-best 119 yards from scrimmage per game since entering the league in 2013.