Though the Panthers are off to a 3-0 start to the season, there is major concern for Carolina.

Standout running back Christian McCaffrey suffered a strained hamstring in Thursday night’s Panthers win over the Texans, Carolina head coach Matt Rhule said after the game. Rhule added he does not know the severity of the injury.

McCaffrey left the field and went into the blue medical tent in the second quarter following a run in which he could be seen favoring his leg after no contact.