Stoke City defender Marc Wilson suffered a broken leg in the Potters' 0-0 draw with Sunderland on Saturday.
The Republic of Ireland international was injured while making a challenge on Black Cats striker Steven Fletcher at the Britannia Stadium.
The 25-year-old wrote on Twitter: "Have broken my fibula. Hopefully I can make a speedy recovery."
Manager Tony Pulis said: "Marc will be out for a while, but we are not sure at this stage for how long."
The injury to Wilson could provide defensive problems for City, who do not have another recognised left-back in their 25-man Premier League squad.
Regular right-back Andy Wilkinson replaced Wilson on Saturday, while Ryan Shotton and Matthew Upson could provide further options for Pulis.