The duo do have offers from Brazil and Vice-President Adriano Galliani is set to fly to South America on Sunday for talks.
"If Pato and Robinho leave then we'll need another striker," Allegri stated on Friday afternoon. "Five attackers is the right number, but it all depends on Galliani's trip.
"From that we will look at what the best solutions are to strengthen the team. But talking about this now makes no sense.
"If a player arrives then it will be an important player and if it is an important player then they would probably have already played in the Champions League this season."