Manchester City midfielder Patrick Vieira will miss the Barclays Premier League match against Liverpool on Sunday as he starts a three-match suspension.
Vieira has been punished by the FA following a challenge on Stoke's Glenn Whelan during the draw in midweek.
Martin Petrov is out with a knee injury with fears he could be sidelined for up to four weeks, while Carlos Tevez is still in Argentina dealing with a domestic matter.
However, Craig Bellamy could come into contention after stepping up his fitness following a knee problem.
Tevez will miss his third game in a row and City then take on Stoke in an FA Cup replay followed by title-chasing Chelsea in a hectic round of fixtures.
Mancini is anxious to see Tevez back in a City shirt sooner rather than later.
He said: "I hope he comes back as quickly as possible. I am frustrated he is not with us. It is a problem as we have some very important games coming up and we need him.
"I don't think he will be here on Sunday but maybe he will come back Monday for the Stoke game."
Liverpool midfielder Yossi Benayoun faces a late fitness test ahead of their trip.
The Israel international has recovered from a broken rib which has sidelined him since January 13, but did not feature in last night's Europa League victory over Unirea Urziceni because of a back problem.
Maxi Rodriguez returns to the squad having been ineligible for the European tie.
Centre-back Sotirios Kyrgiakos serves the second game of a three-match ban while striker Fernando Torres and full-back Glen Johnson are still not fit after knee injuries.
Benitez has tried to play down the significance of the match, with City currently occupying the final Champions League spot one point ahead of Liverpool and with a match in hand.
He believes there is plenty of time remaining in the season for things to change significantly - especially with Tottenham and Aston Villa also challenging.
"It will be an important game for both teams and we will try to win," he said.
"If you cannot, it is better not to lose, but the main thing for us is to try to win.
"We will try to attack and we know we will have to score goals if we want to win.
"They are an attacking team and we will have to attack too, so I think it will be open."
Copyright (c) PA Sport 2009, All Rights Reserved.
Do YOU want to write for GiveMeSport? Get started today by signing-up and submitting an article HERE: https://www.givemesport.com/writeforgms