The Potters have yet to make any new signings since the hiring of new boss Mark Hughes but they are known to be in the market for a left-back.
And Coates has confirmed that Pieters, the 24-year-old who currently plays for PSV Eindhoven, is very much on their radar.
"We are certainly looking for a left-back because we've only got Marc Wilson at the moment, and he was brought in as a midfield player," Coates told The Sentinel.
"We haven't made any decision (on Pieters) because we are looking at options, but he's certainly a possibility."
Pieters has made almost 100 appearances for PSV and has been capped 17 times by the Dutch national side.
He was reportedly on the verge of moving to Newcastle last year, only to be sidelined by a broken metatarsal bone in his left foot.
The fiery character was sent off on his return to action for PSV in January and then smashed a window in the players' tunnel in frustration.