The full-back has not featured for the Villa Park club this season, and his last domestic appearance came in June during a loan spell at Mallorca in Spain.
But Bannan, who made a switch to Crystal Palace in September after finding first-team chances limited at Villa, believes his fellow Scot is wasted at Villa.
"He's been brilliant," said Bannan. "I found it tough fitness-wise, playing for Scotland when I wasn't involved with my club.
"But Alan's performances have been unbelievable. I can't remember the last time he had a club game - maybe on loan in Spain last season.
"I'd say he's the best right-back at Villa, but I don't know all the ins and outs of what's going on there.
"I'm amazed he's not had a move yet. I'm sure something will come off for him in January, as his form with Scotland has been tremendous."
