The former England captain will join up with his new team-mates at Camp des Loges next week, and the Italian boss thinks the 37-year-old will be ready for domestic action soon
There were doubts over the 37-year-old's fitness when he joined the French side, but the Italian trainer will get a closer look at his new signing when he joins up for training next week.
"He's coming on Wednesday, he will start to work at the Camp des Loges with the team and we will look at his physical fitness for, perhaps, the game against Sochaux," Ancelotti told a press conference.
"Training will not be open to the public, only to the media, on accreditation, to avoid a large crowd."
Although Beckham is likely to travel to Valencia with his team-mates for the upcoming Champions League match, the game may have come too soon for the midfielder.
And Ancelotti concedes he has not thought about the Englishman's role in the team.
He said: "I do not know, I have no news about his form. He can play instead of [Marco] Verratti, or right, but he doesn't have the same characteristics as Lucas [Moura]. But he will be useful."