Tatum was upgraded from "out" to "questionable" on Boston's official injury report ahead of Friday's game against the Dallas Mavericks.
Tatum has been making steady progress, including practicing with the Celtics' G League affiliate in February, but he and the team had shied away from giving a timeline for his return.
Tatum was carried off the court in the fourth quarter of game four of the Celtics' Eastern Conference semi-finals loss to the New York Knicks and had surgery on May 13th.
He surprised many in September when he said in an interview with NBC's Today Show that he hadn't ruled out a return this season.
The six-time NBA All-Star, who was a member of the USA's Olympic gold medal-winning teams at the Tokyo and Paris Games, has attended most of the team's games this season while continuing a rehab process he called "exhausting."
Despite Tatum's absence the Celtics have emerged as contenders with Most Valuable Player contender Jaylen Brown leading the way.
They were in second place in the Eastern Conference going into Thursday's games, five games behind the Detroit Pistons and 1.5 games ahead of the third-placed New York Knicks.
Tatum told "The Pivot" podcast earlier this year that he knew his return could affect the current lineup's chemistry.
"I haven't played with these guys or with this group, but (the Celtics have) a lot of high-IQ guys out there," he said. "So if that did present itself, and if I did come back, we professionals will figure it out."