''Chris Houston underwent a significant medical procedure this spring,'' the Lions said in a statement Friday. ''Both parties felt that the best course of action at this time was to release Chris and allow him to rehabilitate away from the Club. The Lions appreciate Chris' contributions over the years and wish him the best in his recovery.''
Houston, who had foot surgery, was limited to 12 games last season because of toe and foot injuries. The ailments appeared to hurt his play when he was on the field. Houston had not attended offseason workouts so far this year under new coach Jim Caldwell.
''We anticipate Chris making a full recovery and playing football this year,'' Houston's agent, Jonathan Feinsod, said in a telephone interview Friday night.
With money saved by releasing Houston, the Lions signed first-round pick Eric Ebron to a four year contract. To replace Houston on the roster, Detroit added undrafted rookie Bryce Quigley, a former San Diego State offensive tackle.
Detroit acquired Houston from Atlanta for a fifth-round pick in 2010. The Lions re-signed him twice, including last year to a five-year deal. Houston had a career-high five interceptions in 2011, helping the Lions reach the playoffs for the first time since the 1999 season. Houston had two interceptions in each of the last two years and has 13 in his career.
He struggled a lot last season and said he was benched for the first time in his career on Oct. 20, 2013, against Cincinnati.
''That was just a wake-up call,'' Houston said after the 27-24 loss to the Bengals. ''That was probably my worst half of football I ever played.''
Houston, who was drafted out of Arkansas by the Falcons in the second round in 2007, has started at least 10 games every season of his career for a total of 91 starts.
The Lions likely will start cornerbacks Darius Slay, a second-round pick last year, and Rashean Mathis, who turns 34 next month, this season. A pair of 2012 draft picks - Bill Bentley and Jonte Green - are expected to get a chance to compete for playing time.
Detroit wrapped up its minicamp on Thursday and will start training camp in late July.
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