On Saturday afternoon, Cotterill played the final six minutes of the goalless draw with Rotherham United as he made his first appearance in the second tier since the start of November.
The winger has been plagued by issues with both his knee and hamstring, but Rowett is hopeful that the Welsh international can enjoy a prolonged period in his team.
His initial comeback in the FA Cup against Bournemouth in January was cut short after he broke down again, but Rowett feels that the Welsh international is stronger this time around.
Rowett said: "We were going to probably leave Cotts until the next game, but we needed another attacking option and he'd looked fit in training.
"We just decided to take a chance and give him some time on the pitch. He's trained really well and he's raring and ready to go.
"He looks different this time to when he came back the last time. He looks far more confident in how he feels and that's good news. We'll be hoping that he'll have a big impact on our season."
Before being sidelined, Cotterill had netted twice in 13 matches in the Championship, but despite his lack of goals, it was his delivery from set pieces and wide areas that helped Birmingham remain in and around a top-six place.
Ahead of Tuesday's home fixture with Bolton Wanderers, the Blues sit five points adrift of Sheffield Wednesday but they do have one game in hand.