Celtic keeper Artur Boruc is looking at three weeks on the sidelines after an operation for a knee complaint. However, the Poland international may have to delay the surgery if The Hoops cannot register back-up keeper Dom Cervi in time.

The American was not included in the Hoops' original 25-man squad submitted to UEFA, but the Parkhead club have asked for special permission to have Cervi involved in Germany on Thursday night.

Boss Tony Mowbray said: "Artur has a thigh injury which will take a couple of weeks to settle down.

"He also has a slight problem with his knee and he'll need something done either immediately or in a few days.

"The over-riding issue is whether we can have another keeper in the squad for Hamburg.

"We are looking at the rules and we believe we can have a replacement as long as we can prove a keeper is injured.

"If we can get Artur's knee sorted now, he could hopefully be ready for the Dundee United game on November 22."