Ibrahimovic: 'Nothing personal' about Barca
Ibrahimovic missed the 2-2 draw at Nou Camp earlier in Group H and will now have to make do with a match that is reduced to a virtual friendly after both sides qualified for the last 16 in the previous round of games.
"I was disappointed but for me playing against a former team is nothing personal," the volatile Swede told UEFA.com. "Of course it's emotional, a big game, but in the end it's like any other game. There's no need to over-hype it."
Ibrahimovic fell out with Barca coach Pep Guardiola when he was offloaded at the end of the 2009/10 season, calling him "the philosopher who has shattered my dream."
"Even when I left the team, I knew I'd left the best team in the world," said the 30-year-old.
"But, for me and all the other parties involved, I think the best solution was to leave the club. Given the results for both sides, it was the best solution.
"I think Milan are the biggest club I have ever played with," added Ibrahimovic, who won three Italian titles with arch rivals Inter Milan before his spell with Barcelona.
"I felt at home from my first day here - they welcomed me with open arms.
"I think this game is more about prestige," he added. "It's good to come first, but sometimes it's good to come second; both can be positive or negative."
Barcelona lead Milan by two points and will guarantee top spot if they win on Wednesday.