Stoke City striker Mamady Sidibe has suffered a major injury setback after being stretchered off in a reserve game on Wednesday.
The 31-year-old was stepping up his return to fitness after being out of action for 14 months.
After scoring in the midweek meeting with Port Vale, he broke down on the halfway line after 72 minutes, holding his knee.
The Mali international missed almost all of last season after snapping his Achilles tendon in a home clash with Tottenham in August 2010.
Potters assistant manager Dave Kemp, who took control of the clash at Vale Park, could not reveal the extent of Sidibe's latest injury.
Stoke are also missing Ricardo Fuller due to injury while Jonathan Walters and Peter Crouch have been regular starters up front this term.