“Igor feels he couldn’t give 120 per cent for the club while he has this problem, only 70 per cent, which he isn’t happy with,” Albion chairman Jeremy Peace told the clubs official website.
“With this in mind, he has decided to retire from English football and return to Slovakia.
“It’s really sad to see him go. Igor has been a great servant to the club.
"He will always be remembered for that penalty at Bradford and will always be welcome back here.
“We hope he makes a full recovery and we wish him and his family all the best in the future.”