Stoke City centre forward Mamady Sidibe has suffered an injury setback during his return from an Achilles injury.

The 31-year-old, who has not played for Tony Pulis's side in 14 months, was stretched off during a reserves match against Port Vale this afternoon with a knee problem.

The extent of the injury has yet to be confirmed, although assistant manager David Kemp has confirmed that is could be serious.

"It seems to be his knee but we're not sure if it's dislocated or not," said Kemp.

Sidibe has been at the Britannia since 2005 when he joined from Gillingham.