The 24-year-old moved to San Siro on loan for the remainder of the campaign in January and has scored twice in nine appearances under Clarence Seedorf.
Having made a reasonably impressive start to life in Milan, agent Vincenzo Morabito expects his client to move permanently at the end of the campaign.
According to Morabito, it would be "extraordinary" for a permanent deal not to be completed, with a fee already settled on.
"Milan will take up their option and there is already a deal between the two clubs to sign him at the end of the season for a reasonable, symbolic price," he told fantagazzetta.com.
"It won't be any more than €3million or €4million. It would mean something extraordinary if that didn't happen."
Taarabt arrived midway through what has been a turbulent campaign for Milan, who appointed Seedorf as Maximiliano Allegri's replacement in January.
