Bannan was expected to be back in Wednesday’s team for their match against Stoke City in midweek, but the midfielder suffered a set back.
And Carvalhal is now sweating over the Scotland international’s fitness, with his knee still causing him some problems.
“I thought Barry [Bannan] would be ready for Stoke but he started to feel a small pain as did ,” he said. “Hopefully he will be better in a few days.”
Bannan has been a key player for Wednesday so far this season, so they will be desperate for him to return as quickly as possible.
The 26-year-old’s energy in midfield has been vital for the Owls, while his creativity has also stood out.
Wednesday have missed Bannan in his absence, and they were beaten 2-0 by Stoke on Tuesday evening, meaning they will be looking to bounce back against Derby.
The Rams are flying high in the Championship table, and they will pose a tough test, but if Wednesday are able to win it would make a statement of their intent.
The Owls are currently sitting in eighth place in the Championship table – level on points with the play-off spaces.