Dallas Cowboys defensive end Tyrone Crawford was carted off the field on Sunday after suffering a lower left leg injury during a drill, multiple media outlets reported.
The injury occurred in the team's first day of training camp in Oxnard, Calif.
The team did not issue a report regarding the specific nature of the injury, but DallasCowboys.com reported, based on sources, that it appears to be a serious injury and might involve damage to his Achilles.
Crawford, a 2012 third-round pick from Boise State, banged his fist to the ground while receiving medical attention.
Crawford was working with the second-team defensive unit. He did not start any games last season as a rookie, but he played in all 16 and had 33 tackles.
The Cowboys are missing five offensive linemen because of injuries,
Defensive tackle Jay Ratliff missed practice with a strained hamstring and it's unclear when he will return. He had an MRI on Sunday.