Zlatan Ibrahimovic's injury setback will not have an impact on Milan's transfer plans for the January window, according to head coach Stefano Pioli.

Ibrahimovic has been out of action since sustaining an injury against Napoli on November 22, but was back involved in first-team training this week.

However, reports emerged on Saturday claiming that the 39-year-old – who has scored 10 goals in six Serie A appearances this season – had suffered a calf strain and will now miss another month.

Pioli confirmed the news in a media conference ahead of Sunday's trip to Sassuolo, though he affirmed Ibrahimovic's new problem will not change Milan's strategy heading into the transfer market.

"It was a strange day, as we were convinced he could recover in time to be in the squad tomorrow and even play a few minutes, then this happened," said Pioli, whose side have been linked with a move for out-of-favour Atalanta star Alejandro Gomez.

"I am very disappointed for him, because he was so eager to return. He'll be back stronger than ever and we have alternatives who can play.

"Ibrahimovic's injury will not change our transfer strategy, although if there is an opportunity to improve the squad, I'm sure the club will evaluate it."

Milan have drawn their last two league games, with city rivals Inter hot on their tails in second place and Juventus four points back.

Of the 11 league matches Ibrahimovic has missed since rejoining Milan, the Rossoneri have won six and drawn five.

It may not just be Ibrahimovic who Pioli is without, however, with Ante Rebic also struggling after sustaining a knock against Genoa on Wednesday, while Rafael Leao is not in good form.

Pioli continued: "The plan remains to play attacking football. Rebic hasn't scored lately, but only due to the opposition goalkeeper making great saves and some bad luck, but I am very satisfied with his contribution and movement.

"Leao struggled with that injury and spending so much time off the field can affect your tempo. His last few performances have not been up to standard.

"Rebic went off against Genoa on Wednesday because he had a problem with his foot. He's been training separately over the last couple of days and I hope he'll be ready.

"We need a great performance against Sassuolo as they are a team to be faced with a very clear head. The team won't suffer from Ibrahimovic's injury because it is a side that always attacks and creates chances anyway. It is a squad with quality throughout."

After beating Milan four times in their first six Serie A meetings, Sassuolo have since lost eight of the last eight, drawing the other two.