Victory at the Keepmoat Stadium will be enough to propel United into the play-off places due to the rest of the Championship not being in action until tomorrow.
With one win in Doncaster to their name already this season, Leeds could be considered favourites going into a game that is being shown live on Sky Television.
However, such have been the number of changes at Rovers since United’s 2-1 Carling Cup win in late August with Dean Saunders replacing Sean O’Driscoll as manager and several high-profile signings having been made, Grayson is expecting a very different task tonight.
He said: “It is a far bigger challenge than in the Carling Cup. We had a different team out that night and they certainly did, plus they have a new manager with different ideas.
“I don’t think what happened in the Cup will have any bearing on those players who will be involved this time.”
Saunders was brought in by Rovers chairman John Ryan to halt a shocking start to the season that had yielded just one point from the opening seven games under O’Driscoll.
The appointment appears to have done the trick with Doncaster having since claimed seven points from a possible nine to move off the foot of the table and up to 20th place.
Grayson added: “Dean is a colourful character who has got the players playing for him. They are doing things a bit differently as to how they were done under Sean.
“That is down to Dean’s style of management. I saw Doncaster play Hull the other week. They looked to have gone from being a passing team who keep the ball to being a little bit more direct with Jon Parkin up front giving them an outlet.”
Saunders’s appointment may have taken some in the game by surprise, the former Wales international having been given the opportunity to step up three divisions after a successful stint in non-League with Wrexham.
But that is nothing compared to the shock caused by Rovers having since brought in such high-profile signings as England international Chris Kirkland, former France defender Pascal Chimbonda and Herita Ilunga of West Ham.
For Leeds, tonight’s game offers a chance to extend their current unbeaten run to five games.
Robert Snodgrass’s return to training yesterday after pulling out of the Scotland squad the previous week is, therefore, a major boost, as is the return of Finland duo Mikael Forssell and Mika Vayrynen from international duty along with Republic of Ireland pair Darren O’Dea and Andy Keogh.
Grayson added: “It would be nice to win as we would move into the top six. That shows the nature of the division in that you can win a couple of games and get into the play-offs. Lose a couple and you are at the other end. That is how tight things are.”
Tonight’s game kicks-off a hectic period for United, who face seven games in just 23 days.
Grayson said: “The squad will come into play. Periods like this are why I’ve got the strength in depth we have.”