Birmingham City have secured the services of Jonathan Grounds on a two-year contract.
The 26-year-old was due to become a free agent later this summer when his deal with Oldham Athletic expired.
Speaking to the club's official website about his latest recruit, manager Lee Clark said: "I am delighted to welcome Jonathan to the club and he is somebody who both myself and [chief scout] Malcolm Crosby know a lot about from his time at Middlesbrough.
"Jonathan's versatility will be important for us as he can play as a left-back or left-sided centre half. We conceded far too many goals last season so it was key that we strengthened our defence and Jonathan will help us to do that.
"He has a lot of experience and I can see in his eyes that he has that hunger as he was always determined to get back playing in the Championship."
Grounds started his career with Middlesbrough before making the move to Oldham in 2012.
