CB Chris Houston has toe surgery

ALLEN PARK, Mich. -- The Detroit Lions have not started organized team activities, but they might already be down a defensive starter through the start of training camp.

Cornerback Chris Houston, who played through a toe injury in 2013, had surgery this week according to the Detroit Free Press, and Lions coach Jim Caldwell said Friday he wasn't sure Houston would be available when training camp opens in July.

"I'm not certain, to be honest with you," Caldwell said. "I kind of leave those things up to our physicians. Those guys went to school for a long time to get those medical degrees, and so what I do is try to focus in on what we're doing and I let them sort of navigate through it and give me an indication of it at some point in time."

Houston posted on his Instagram account about the surgery, and his father confirmed to the Free Press that the surgery occurred.

Earlier this offseason, both Caldwell and general manager Martin Mayhew expressed some concern as to whether or not Houston would return to his form from prior to 2013.

The 29-year-old had 44 tackles and two interceptions in 12 games last season. He was inconsistent throughout the year, though, and was even pulled from one game due to performance. The 44 tackles were a career low.

Houston is expected to be one of Detroit's starting corners, potentially alongside second-year pro Darius Slay. Caldwell declined to answer how the Lions would replace Houston if he were not available by the beginning of camp. Potential options could include veteran Rashean Mathis, who emerged as the team's top cornerback a season ago after signing during training camp, Jonte Green, Chris Greenwood and Bill Bentley.

Green and Greenwood both played in place of Houston when the Lions had injury issues at cornerback last season.