The former Real Madrid player spent last season at Everton after losing his place at Celtic, but was unable to revive the form he showed in an earlier spell at Goodison Park.

Gravesen would relish a move back to the Premier League, while Championship side Wolves have been linked with a move for the 32-year-old.

Asked whether Gravesen would return to Celtic for pre-season training, the Dane's agent John Sivebaek said: "I think so."

He struggled to impose himself on the Scottish game in his first year at the club, prompting Celtic to let him leave on loan.

Former Denmark star Sivebaek has not heard from any clubs about his client, and is not convinced there is an obvious route way out of Celtic, where Gravesen has 12 months of a lucrative three-year contract remaining.

"I don't know, I've got no idea to be honest," said Sivebaek. "I've not heard anything about Wolves."