Derby pair Graeme Shinnie and Mason Bennett will be out for “a few months” with injury, says boss Phillip Cocu.
Scotland midfielder Shinnie, 28, started seven Championship games in a row until coming off with a hamstring problem against Preston on Saturday.
Forward Bennett, 23, has played nine games this season and will be out for a similar period with an ankle injury.
“We’ve had a little bit of bad luck with injuries – in almost all the cases it’s a serious one,” Cocu said.
He told BBC Radio Derby: “I think both, you’re talking about months – a few months.”