Derby have suspended manager and former Newcastle coach Nigel Pearson.
Press Association Sport understands the suspension is pending an internal investigation by the Sky Bet Championship club.
The move follows a meeting between Pearson and Derby owner and chairman Mel Morris at the club's training ground on Monday afternoon and the Rams released a statement just hours before their league fixture at Cardiff on Tuesday.
"Derby County can confirm that manager Nigel Pearson will not be carrying out his duties at tonight's game at the request of the club," the statement read.
"Assistant manager Chris Powell will take charge of the team for this evening's Sky Bet Championship match at Cardiff City. The club will make no further comment at this time."
Former Leicester manager Pearson signed a three-year contract with Derby during the summer and was tasked with emulating the job he did with the Foxes, by winning promotion to the Premier League.
However, Derby have made a disappointing start to the season and are 22nd in the table with just one league win from their nine matches.
Home supporters have had little to cheer with the Rams scoring their only Championship goal at the iPro Stadium so far during Saturday's 2-1 defeat to Blackburn.
Following that loss, Pearson was critical of his players, saying they were "paralysed by fear" and he threatened to replace some of the club's senior players with members of the youth team.
"I can't keep hoping that players are going to bring their best games to the table week in week out, and then not do it, so I might have to start making changes," said Pearson after the Blackburn defeat.
"If that means introducing some of the younger players then so be it."