Johnson arrived at Derby for a £6 million fee, as valued by Sky Sports, and he has made an immediate impression at the iPro Stadium.
The 28-year-old central-midfielder has gone straight into Derby’s first-team, and his performances have caught the eye very quickly.
“He was bought on transfer deadline day and Derby spent a lot of money - £6m - but Bradley Johnson has been the most influential player out of all those they've signed,” Hinchcliffe said.
“It was a bit of a surprise to me that Norwich let him go because he was instrumental last season in helping them get promoted. You can see why - once, perhaps they knew he was on the market - Derby steamed in and snapped him up.
“He's got experience, he's got a wonderful left foot, he's competitive, and he scores and makes goals. He fits Derby's mould really well. The way they want to play, the system they operate in midfield, he fits that perfectly. He's been fantastic since he's been there.”
Hinchcliffe’s surprise at Norwich willingness to sell Johnson was shared by a number of observers, as he was so crucial to them last season.
Johnson had been a key part of Norwich’s side as they achieved promotion to the Premier League, but Alex Neill was happy to relinquish the central midfielder when Derby came in.
Derby are now in fifth place in the current standings, and they have lost just one of the 11 matches that Johnson has played for them.