The Ireland Under-21 skipper has been in inspired form this campaign after he was surprisingly slapped on the transfer market by former manager Paul Sturrock although new boss Brian Laws has now reportedly made him 'unavailable'.
With the additions of Kenny Lunt and Yoann Folly to the midfield in the summer, Whelan has shrugged off the competition and established himself as perhaps the first name on the team sheet.
Bullen told Footymad: "Consistently, Glenn is our best player this season. I have often been asked the question which one of our young players can go all the way and I have always said Glenn Whelan.
"Everybody knows that he has the quality, last season I think he tried to play the World Cup ball once too often and that can affect confidence, but now he has reverted to playing it simple and he has also got that bit of devilment in his play, I don't know if it's a bit of that Irish Roy Keane-type character but he isn't afraid to put his foot in and get angry."