AC Milan head coach Massimiliano Allegri is confident his side will overcome an injury list akin to a "wartime news bulletin" and raise their game for Champions League opponents Celtic.
Kaka joined the long list of players who will miss the San Siro encounter on Wednesday night when he was diagnosed with a adductor muscle tear on Monday after going off against Torino on Saturday.
Milan came back to avoid a second defeat in three Serie A games thanks to Mario Balotelli's penalty, which made it 2-2 with the last kick of the ball.
But the point came at a cost with Kaka, captain Riccardo Montolivo and fellow midfielder Andrea Poli all suffering injuries that rule them out of the Group H opener.
Forwards Stephan El Shaarawy and Giampaolo Pazzini are also out along with defenders Ignazio Abate, Mattia De Sciglio, Matias Silvestre and Daniele Bonera.
Quoted on his club's official website, Allegri said: "We didn't play well on Saturday, actually, we played very badly against a Torino side that caused us a lot of problems.
"Wednesday will be a different game as they always are in the Champions League. It's a great atmosphere. The start of the group stages.
"It's a big match as we'll be up against a team that are very physically strong as well as being technically good players, especially in the attacking department. They'll be a tough team to face.
"I think that the players will put in a good performance tomorrow to put the match in Torino behind us.
"We're playing at home as well so we'll have our fans behind us as well just as they were in the match against PSV (when Milan won 3-0).
"There are all the ingredients for a great match and a great performance. I'm not worried at all about the situation.
"This period that we're going through, we've actually been a bit unlucky. The number of injuries we have reads like a wartime news bulletin but nevertheless, the work done by the medical staff and the physiotherapists has been outstanding."
While Celtic will be relieved not to face Kaka, whose goal knocked them out of the last 16 in 2007, they will come up against a striker who helped put them to the sword at the same stage last season.
Alessandro Matri scored in both legs of Celtic's 5-0 aggregate defeat by Juventus before moving to the San Siro in the summer.
Matri said: "It'll be an emotional night. My Champions League debut in the San Siro. I can't wait to get on the pitch and play this game."
Allegri revealed Matri would start up front alongside Balotelli with either Robinho or Slovenia international Valter Birsa playing off them.
Holland international Nigel De Jong will play alongside former Portsmouth player Sulley Muntari and Italy international Antonio Nocerino in midfield.
Celtic boss Neil Lennon admits he is struggling to find sympathy for Milan's injury woes.
Lennon, who revealed midfielder Joe Ledley was a "major doubt" with a groin injury and who will also be without winger James Forrest and midfielder Beram Kayal, said: "It is very unfortunate for him that these injuries have come all at the one time and it is not an ideal situation.
"But I am sure as the season and the campaign progresses Milan as always will get better and stronger.
"I can't look too much into Milan's problem I have to concentrate in my own.
"The fact that he can maybe bring Matri in to the team, he cost a lot of money, money that myself or my board of directors can only dream of paying for players.
"I can't really offer up a lot of sympathy at this stage for him."