The United States international has lost his starting berth to new signing Phil Bardsley and now faces a spell on the sidelines after it was revealed that he requires surgery.
Stoke assistant manager Mark Bowen told The Sentinel: "It's been troubling him for a while, so the time has come for an operation.
"He started feeling it last season, then obviously went to the World Cup and came back to us still feeling a bit sore.
"These things tend to manifest themselves over a period of months and now the time has come, but it's difficult to say how long we will lose him for."
Bowen was able to deliver a more positive outlook on midfielder Stephen Ireland and winger Oussama Assaidi.
Ireland has been out with a pulled muscle in his rib cage, but could come back into contention for the Premier League clash against Leicester City on Saturday.
"He came through training okay," said Bowen.
"And if he isn't ready for this weekend, then I'm sure he'll be banging on the door for the weekend after."
Assaidi has been troubled by knee problems, but Bowen revealed that the on-loan Liverpool man has impressed in training this week.
The former Wales defender said: "He's been training all week and looked good.
"We are taking things easy with him because he hasn't had a pre-season. But everything we've thrown at him in training he has come through."
Bowen added that Peter Odemwingie's knee surgery was a success and the club's medical team will put together a plan for his rehabilitation once the swelling has gone down.
