Leeds fans are disappointed at the limited opportunities given to Nlketiah, as he has been on the bench for most of their Championship clashes.
Mills believes that it is clear Bielsa does not trust the 20-year-old, while Bristol City are lurking for a possible January loan for Nketiah.
He told Football Insider: "He just hasn't really had a chance at Leeds from the start.
"It's an interesting one, clearly it's something that Bielsa doesn't quite see in training, playing international football is different, it's not the same as playing league football and certainly Championship football.
"You have to trust Marcelo Bielsa and say what is he not seeing in training?
"What is not happening for him to not be put in the starting line-up?
"There's just something that isn't right. Bielsa clearly doesn't trust him yet."