Ibrahimovic missed the opening leg through injury but will lead Milan's attack on Wednesday as the Italians chase first place in Group H against the holders.
Barca midfielder Sergio Busquets believes too much attention has been shown to Ibrahimovic.
The Swedish striker, who has scored in the three European matches he has played for Milan this season, will take on Barca for the first time since leaving the club in the summer of 2010 after just one year with the Catalan outfit.
Ibrahimovic openly criticised Barca and coach Josep Guardiola in his autobiography which came out this month.
"All has been said already," said Busquets.
"We are playing against Milan, not against Ibrahimovic.
"It will be the same for Ibrahimovic too, a game against Barca and not against a former team-mate."
The clash is between two sides that have already qualified for the last 16 of the Champions League, and Barca, who are two points clear of Milan, would guarantee themselves top spot with a win.
"Our focus is on getting three points that will mathematically assure us the first place," added Busquets.
"We will go out for victory from the start.
"We know a win in Milan will give us prestige and a big boost in confidence."
The Spaniards will have to overcome the absence of pivotal midfielder Andres Iniesta, who sustained a muscle injury in his team's 4-0 triumph at Zaragoza at the weekend.
Barca, second in the Primera Division behind leaders Real Madrid, are also without suspended defender Dani Alves and assistant coach Tito Vilanova after the latter underwent gland surgery in Barcelona.
Barca will have to keep a close eye on Alexandre Pato, who put Milan ahead inside 30 seconds in the 2-2 draw between the two sides in their group opener at the Nou Camp.
The Brazil international is set to start against Barca having played as a second half substitute in Saturday's goalless draw at Fiorentina after two months on the sidelines through injury.
"It was great to return to play," said Pato.
"I was unlucky not to score as I hit the post but I was happy with my performance.
"I hope I will score against Barcelona."
The result in Florence extended Milan's unbeaten run in Serie A to six games and lifted Massimiliano Allegri's side to third, one point behind league leaders Juventus.