BALTIMORE -- The Detroit Lions have placed cornerback Drew Coleman on injured reserve and claimed former Dallas Cowboys guard Bill Nagy off waivers.

Coleman recently sustained a concussion, and was being held out of practice as a precautionary measure. It appears his brain injury was more severe than expected.

"Drew Coleman is currently sidelined with a concussion, so he hasn't been out here in a couple of days" Lions coach Jim Schwartz said on Wednesday. "He wasn't even at the facility, so when he's able to get back out, when' he's 100%, we'll get him back out. But you guys know that protocol is a very serious thing in the NFL and across sports.

"Not just football, not just NFL football, college football, high school and everything else so we'll take him day-by-day."

Nagy, who played at Wisconsin, was a seventh-round draft pick by the Dallas Cowboys in 2011. He started in four games as a rookie, but fractured his ankle and was placed on the injured reserve list. Nagy was waived on August 15, 2012 after suffering a high ankle sprain on the same ankle he had fractured the previous season. According to ESPN, Nagy had surgery performed by Dr. Robert Anderson in Charlotte, N.C., on his left ankle on Wednesday.

Nagy could start this season on the physically unable to perform list for Detroit. Even if he does not play in 2012, Nagy has the potential to start for the Lions - if healthy - next year.