'Who knows what to expect?' Rotherham United boss Paul Warne on tonight's derby trip to Sheffield Wednesday
The Millers, 3-0 winners at home to the Owls earlier in the season, were already deep into their preparations for this evening's showdown when news broke on Monday that their opponents had lured Darren Moore away from Doncaster Rovers to become their new boss.
That has left them playing a guessing game as they try to work out what tactics Wednesday will adopt in a clash that sees two sides in the Championship drop zone go head to head.
"We had a pretty good idea of how Wednesday would play but now it's like the first game of the season," Rotherham boss Warne said.
"We don't know what system they will play or anything. Darren could try to impose his methods straightaway or he might leave it for one game before changing things."
Warne, a friend of Moore's through the TV work the pair have done together, was as surprised as anyone by the announcement.
"It was a massive shock," he said. "In football, you generally get to hear about things before they happen but that wasn't the case this time.
"Our analyst mentioned it in Monday morning's meeting about how we thought Sheffield Wednesday were going to play.
"We all checked our phones, thinking: 'It can't be right. None of us know.' It was on the official Sheffield Wednesday website and we were still thinking: 'It can't be true. It's got to be a fake site.'
The Millers have a centre-half crisis as they head to S6 trying to half a run of five successive defeats, with Clark Robertson sidelined by a hamstring pull, Michael Ihiekwe suspended and Richard Wood struggling to recover from a groin injury.
They are also well aware that the Owls, who have taken no points from their last four matches, will be lifted by Moore's arrival.
"It's a great appointment for them," Warne said. "Darren did brilliantly at West Bromwich Albion and was harshly treated there when he lost his job. Then he did a really good job at Doncaster.
"Of Wednesday's last few managerial appointments, he is the stand-out one. I'm not over the moon about it because I'm competing with him for survival."
The manager is adamant last October's derby success at AESSEAL New York Stadium will have no bearing on tonight's encounter.
"We played well against them and took our chances. In recent weeks, we've played well and not taken our chances," He said.
"We've beaten them once already but when the whistle blows on Wednesday that will have no effect on the lads' psychology. It's all about how well you can start the game and can you impress your style on to theirs?
"It's gloomy reading for a Rotherham fan if you look at the league table. It was like that after the Watford game (December 8) but then we put a few good results together and clawed ourselves out of it. We'll have to do the same again."