The 28-year-old Honduran joined the Potters from Tottenham for £8m in August 2011 but made only four appearances last season.
"I'm not sure whether Stoke are willing to let him go. If he became available I'd be interested," Bruce told BBC Radio Humberside.
"He's a player I like and one I brought to England."
Bruce added: "If Stoke say he's surplus then we would look at that."