Vikings defensive end Brian Robison suffered a pectoral injury while working out at Winter Park today, league sources confirmed.

Robison said in a text message that "I'll be OK," but didn't elaborate on the extent of the injury. Medical tests were pending.

The Vikings through a spokesperson declined comment on the injury.

Robison has been a full-time starter for the Vikings the past four seasons, playing and starting in 63 of a possible 64 games. The 32-year-old started every game in 2014, Mike Zimmer's first season as coach, but he had just 4.5 sacks and 24 tackles, his lowest totals since becoming a starter in 2011.

The Vikings have used a third-round pick in each of the past two drafts on defensive ends. In 2014, they selected Scott Crichton to back up Robison at left end. He played sparingly as a rookie, though. Earlier this month, they drafted Danielle Hunter, a speed-rushing right end, in the third round, too.

The Vikings also have a trio of unproven defensive ends on their 90-man roster in Leon Mackey, Caesar Rayford and Justin Trattou.

FOX Sports first reported that Robison had suffered a pectoral injury.