Reading's Roberts set to miss rest of season
Roberts has been sidelined since December and he admitted last month that the club's medical staff had "exhausted everything they can to try and make it (the injury) right".
The 35-year-old had hoped to recover before the end of the season, but he revealed on Twitter that he will need an operation to cure the problem.
"Injury Update. Rehabilitation has not been successful. Seems at this point Surgery is our only option, meaning my season is over! Gutted", he tweeted.
"Everything that could have been done has been done but the most important thing is P.L. football for Reading FC next season."
Roberts' absence is badly timed for second-bottom Reading, who have won just five times in the league this season and face a crucial home clash against fellow strugglers Aston Villa on Saturday.
The former West Bromwich Albion and Wigan star was a key player during Reading's promotion campaign last term, scoring six times as Brian McDermott's team won the Championship title.