The midfielder joined the Championship side at the start of the season.
The midfielder moved to Hillsborough in the summer and has played an integral role for Carlos Carvalhal's side, helping the club put themselves right into the promotion picture in the Championship. And Bullen offered an explanation as to why Bannan has been so impressive since joining the club.
"Barry is the type of player who you watch on the side of the training pitch and you just admire his quality," he told the Star.
"He's a brave, brave player. He demands the ball when things are going against the team. He always wants the ball. His awareness of what's around him is brilliant."
The 26-year-old's influence on the side has clearly not gone unnoticed by Carvalhal, who handed him a new deal with the club last month, along with several other key members of the squad (via Sheffield Telegraph).
That decision to hand numerous players new contracts highlights Wednesday's desire to build a side that can grow together, and perhaps lead the team into the Premier League, and Bannan is clearly an important part of that core group.
And that strategy is seemingly paying off as the club currently occupy a place in the top six, and have the kind of momentum on their side that could see them move into contention for a place in the automatic promotion positions. And Bullen appears to have little doubt that if the team are to achieve that, it will be Bannan who takes them there.