McCarron was forced to leave practice Tuesday due to a right thumb injury, Aaron Wilson of the Houston Chronicle reports.
It's unclear how he picked up the injury, but he seemed to hurt his right throwing hand Tuesday, and didn't return to practice. McCarron stands to back up Deshaun Watson in Houston, so don't be surprised if the team doesn't rush him back for Thursday's preseason game against Green Bay. If the Alabama product doesn't play, third-string quarterback Joe Webb stands to take on an increased workload.