Three weeks into his return from an ACL tear, Jonathon Brooks injured his knee again.

The rookie Carolina Panthers running back slipped to the turf and limped toward the sideline with a non-contact knee injury in Sunday’s 22-16 defeat against the Philadelphia Eagles. On Monday, the team announced that Brooks had torn the ACL in his right knee.

The injury is a tough blow for the promising rookie whom the Panthers selected out of Texas in the second round of April’s draft.

The injury took place in the first quarter with the game in a scoreless tie. Brooks slipped to the turf on a cut and was in obvious pain. He tried to walk to the sideline, but fell again before he made it.

Brooks was one of college football’s top running backs at Texas and considered a potential first-round prospect. He tore the ACL in his right knee in November last season and dropped to the second round (No. 46) to the Panthers. Even with his injury, he was still the first running back off the board in the draft.

Brooks sat out of Carolina’s first 10 games while recovering from his injury before making his NFL debut in Week 12 against the Kansas City Chiefs. He rushed eight times for 25 yards in two games while backing up Chuba Hubbard. Now, three games into his pro debut, Brooks is facing another extended absence.

With Brooks injured, Hubbard returns to a bell-cow role as Carolina’s starting running back.