Ibrahimovic's return to San Siro has coincided with a marked upturn in form from Milan, which has won five of its past six matches in all competitions.

But the 38-year-old, who has scored two goals since his move to Milan, including one in extra-time in the 4-2 Coppa Italia win over Torino last time out, is unlikely to feature in Monday's (AEDT) encounter after coming down with an illness.

"Over the last two-three days, Ibrahimovic and [Simon] Kjaer have been suffering from flu and I doubt we're going to be able to call them up," Pioli said.

"There are muscular problems for [Rade] Krunic too, so yes, we have more than a few problems.

"Hellas Verona are in good shape, doing great work this season and will arrive at San Siro very determined. They run hard and it has been a difficult week for us."

Ibrahimovic's absence means Rafael Leao and Ante Rebic are Milan's forward options, with the club having sold Krzysztof Piatek to Hertha Berlin late in the January transfer window.

Milan did not get a deal for Wigan Athletic defender Antonee Robinson over the line but recalled Diego Laxalt to fill the void left by Ricardo Rodriguez, who departed on loan to PSV.

Suso also left for Sevilla, with Alexis Saelemaekers joining Milan to add to the signings of Ibrahimovic, Kjaer and Asmir Begovic.

"We brought in players of quality and experience, but also interesting young prospects," Pioli said of Milan's business. 

"Whoever plays instead of Ibrahimovic, he will do well, and it's not the system that decides victory.

"We've turned a corner lately because the team understood that only with the spirit of sacrifice can we achieve a win. It was a good January, but that is behind us now and we have new important games to play."