Arsenal's Belgium international centre-half Thomas Vermaelen has suffered a setback in his recovery from an Achilles injury and will be out for the foreseeable future.
The 24-year-old was close to a return to action after more than two months on the sidelines, but suffered a recurrence of the injury during training on Monday.
Manager Arsene Wenger told the club's official website:"We don't have good news about Thomas Vermaelen. He had a little set-back in training and he has to see specialists again.
"I don't know where we go with Thomas time-wise, but at the moment he cannot play. I can't give you any timescale at all.
"On the scan his Achilles is completely clear, but as soon as he stays out for a while it tightens up and he has pain. We don't know the source of his pain."
Vermaelen joined the Gunners in the summer of 2009 from Dutch giants Ajax and has since made 48 appearances for Wenger's side, scoring eight goals.