Former Liverpool midfielder Naby Keita will miss the start of the season for Werder Bremen after being injured while preparing for a friendly.

The 28-year-old Keita suffered a groin problem before Sunday's game against VfB Oldenburg, forcing him to miss the match.

Bremen coach Ole Werner said at the time it was a precautionary measure, but on Monday it became apparent that the injury was more serious as the club announced he will miss “several weeks.”

“We have to assume that Naby won’t be available for us for the first games of the season,” Werner said.

Guinea international Keita joined Bremen on a free transfer from Liverpool in June. He only managed 13 games for the English Premier League club last season, in part because of injuries.