The Tigers boss recently confirmed that he would be interested in bringing the 30-year-old Honduran to the KC Stadium.
"I think it's drifting further away," Bruce told the Hull Daily Mail.
"There's been a change of manager at Stoke and if Tony Pulis was still the manager I'd think there would have been a deal to be done.
"I'm not so sure they want to let him out. If that's the case, we'll move on. Of course I'd be interested but if he's not for sale, he's not for sale."
Palacios joined Stoke from Tottenham Hotspur in 2011.