West Brom and Republic of Ireland midfielder James McClean will face "internal disciplinary proceedings" after he refused to attend the club's four-day training camp in Scotland.
McClean, 29, has made 99 appearances in three seasons with the Baggies.
The Championship side said he "failed to report without permission".
Last month goalkeeper Ben Foster, who has since joined Watford, and defender Craig Dawson were fined for not going on a pre-season tour to Portugal.
"Another disruption for new boss Darren Moore" - Analysis
BBC WM sport reporter Rob Gurney:
"So James McClean follows the stance adopted by Foster and Dawson earlier in the summer, and refuses to go on a pre-season training camp.
"Foster got a move to Watford, and there's nothing to suggest McClean won't go to Stoke, as has been widely reported.
"Ironically, Dawson has been given permission to miss this trip as he's just become a father.
"But it's another disruption to plans for the new season that new Baggies' boss Darren Moore could have done without.
"And the professionalism of those players involved, or lack of it, has to be called into question, too."