The Detroit Lions have suffered their first injury of training camp.
Tailback Theo Riddick participated the first two days of camp, but missed Sunday's padded practice due to an issue that coach Jim Caldwell declined to disclose. He watched from the sidelines in shorts and a baseball cap.
"Anytime you don't have someone out there you'd like them to be out there working," Lions coach Jim Caldwell said. "But he'll be all right."
Riddick is coming off a season in which he set club records for receptions and receiving yards by a tailback, and figures to have an equally expansive role in the new Jim Bob Cooter offense. Ameer Abdullah and Stevan Ridley both returned in time for the start of training camp on Friday, though Abdullah is wearing a red no-contact jersey. His activity has ramped up the past two days, though, working as the club's No. 1 tailback and also shagging punts.