The City talisman, 35, has been out injured but the form of Michael Rankine in his absence has impressed the York boss and the club's fans.
Now, the Minstermen's manager has a big decision on his hands.
There may not be room in the team for both ahead of York’s trip to Southport on Saturday and Mills told the York Press that there is some thinking to do.
“The way we have played in the last four games doesn’t make it easy to play both of them,” Mills said.
“The way Ranks has been playing and having scored two goals at the weekend, Jon has been in the game long enough and knows that, even if he is fit on Saturday, it does not mean he will play.
“For myself, to have a goalscorer like Jon on the bench or somebody like Ranks, is good news.
“Ranks’ hunger has been nice to see for somebody of his age who has spent two seasons away from full-time football. He wants to play and get the club back to where we should be and want to be.
“He’s also getting fitter and full-time training is making him stronger again.”