Birmingham have given Garry O'Connor a six-month deal, with an option for a further six months.
The 27-year-old Scot suffered an injury-plagued season last year, missing the bulk of the campaign after undergoing double hip operations. The Lokomotiv Moscow striker made only six appearances all season, all as a substitute, scoring one goal.
Manager Alex McLeish said: "Garry has had a chronic groin and hip injury and it probably goes back to his Hibs days and the days he spent in Russia when he played on a synthetic surface."
He added: "Having two hip injuries simultaneously wasn't easy for him.
"If you imagine him fully fit without those problems then that's what we've got to see - what Garry can produce without these hiccups. It was a successful operation and barring major breakdown there's no reason why he can't go on to have a successful career."
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