The Dallas Cowboys may have lost their best cover cornerback.

Orlando Scandrick went down with an injury Tuesday at Cowboys practice and early indications are that he tore his ACL, a source told FOX Sports 1 NFL insider Mike Garafolo. Scandrick will undergo an MRI to confirm the injury.

Scandrick was carted off the practice field shortly after the injury occured, according to multiple reports on scene.

Here's a photo from the scene:

A fifth-round pick in 2008, Scandrick has emerged as the top cover man in Dallas' backfield. This would be another huge blow in an already injury-riddled NFL preseason.