The newspaper, citing sources, said Dykstra is expected to be freed Sunday.
Dykstra, 50, pleaded guilty in Los Angeles to three counts of grand theft auto and to filing a false financial report. He was sentenced in March last year.
Christopher Frankie, author of "Nailed: The Improbable Rise and Spectacular Fall of Lenny Dykstra," told the Inquirer he was surprised at the early release because Dykstra was so "brazen."
Dykstra, a center fielder, played for the Mets between 1985 and 1989 and went on to the Phillies until his retirement in 1996. He helped take the Phillies to the World Series in 1993, although they lost in six games to the Toronto Blue Jays.
In the years before his guilty plea, Dykstra was accused of sexual misconduct, bankruptcy fraud and other wrongdoing. He was sentenced after completing a stint in drug and alcohol rehab.
"I hope, for his sake, his family's sake, and the public's sake, that he doesn't return to his criminal past," Frankie said. "I think people in this country really love a comeback story, so he certainly has that opportunity. But I'm not convinced that's the path he's going to take."