BARCELONA, Spain (AP) — Barcelona says defender Thomas Vermaelen has had surgery to treat a right leg muscle injury and is expected to be sidelined for another four months.

The 29-year-old Vermaelen has yet to play for Barcelona since it paid Arsenal a reported 19 million euros (then $25.4 million) last offseason.

Vermaelen arrived to Barcelona injured from the World Cup, where he played for Belgium.

Injuries limited him to 14 appearances for Arsenal last season.

Barcelona is banned from the next two transfer windows by FIFA for breaking rules regarding the signing of youth players.