Wilson Palacios has had surgery after the Honduran midfielder was a very late withdrawal from Stoke's line-up against Liverpool on Saturday.
Palacios had been named in Mark Hughes' maiden starting 11 as Stoke's manager and took part in the pre-match warm-up but after complaining of 'shooting pains in his stomach', the 29-year-old midfielder was replaced by Marc Wilson and sent to hospital.
While the exact problem has yet to be revealed, Stoke have confirmed Palacios underwent a 'minor surgical procedure' and will be out of action for 'a few weeks', while the club's assistant manager Mark Bowen speculated the midfielder may have had his appendix removed.
"In the warm-up he felt shooting pains low in his stomach," Bowen told This is Staffordshire.
"We thought he might be able to go into the game and see how he got on but he came into the dressing room after the final warm-up doubled up with the pain.
"They will keep him in for tests but we don't know what it is.
"It could be gastro enteritis or maybe his appendix. We just don't know."
Stoke later confirmed surgery had been required via a written statement on their club website.
"Stoke City can confirm that Wilson Palacios was taken to hospital in Liverpool after an incident occurred in the pre-match warm-up which required immediate medical attention," the statement read.
"Wilson has successfully undergone a minor surgical procedure from which he is now recovering from and is likely to be sidelined for a few weeks."