MILAN, Italy, April 14 (Reuters) - service ac Milan coach Stefano Pioli said he is unsure whether veteran striker Zlatan Ibrahimovic will retire from playing at the end of the season, with the Swede still out of action with a knee injury.

Ibrahimovic's contract expires at the end of the current campaign, with the 40-year-old yet to sign a new deal, despite widespread reports in the Italian media saying he will do so.

He has started just 11 Serie A games this season, with Pioli adding that Ibrahimovic will again be missing for Milan's clash with Genoa on Friday.

"Ibra will remain out for a week or 10 days. We hope he can return for the final part of the season," Pioli told a news conference on Thursday.

"Everyone can have physical problems, he is dealing with a knee issue now.

"As for his future, I don't think anything has changed over any plans to retire, but I am not sure.

I am sure he will make the best choice, and we will back him regardless of what he decides."

There was better news on the injury front for Milan, who hold a two-point lead over rivals Inter Milan at the top of Serie A, with Croatian forward Ante Rebic and Algerian midfielder Ismael Bennacer available again.

Milan are looking to win their first Scudetto in 11 years this term, but have drawn their last two matches 0-0 to allow Inter to close the gap.

"We are playing energetic football, trying to dominate the games and create more," Pioli added. "It is right to believe in winning the title until the end because we are strong.

"We have been in front of everyone for a long time - you are not there by luck - but also we are not winning now due to bad luck, we have to put in something more.

"All together we are stronger - the team will give their all until the end because we believe in it, we have quality." (Reporting by Peter Hall Editing by Toby Davis)