ESPN's Rachel Nichols reported the news Saturday.
Lowry said after the game the injury was not related to the offseason surgery he had to repair ligaments in his left thumb.
"Originally, we thought it was something in the nail bed because the nail bed turned black and blue," he told reporters. "We got some X-rays, and we sent the X-rays off to the doctors, and there was a small fracture in the thumb."
Also, Serge Ibaka sprained his ankle in the victory.
Lowry was off to a strong start to the 2019-20 campaign with his offensive role increased following the offseason departure of Kawhi Leonard. The 14th-year guard is averaging 21.8 points, 6.5 assists and 4.3 rebounds while shooting 42.6 percent on threes through eight games.
A two-week timetable would make the Raptors' Nov. 23 clash at the Atlanta Hawks the earliest possible return for the five-time All-Star. The team will likely play it safe given his history of thumb injuries and its 6-2 record, though.
Fred VanVleet will take over the team's point guard duties, while Norman Powell should slide into the starting lineup at shooting guard. Terence Davis could also get more playing time in the backcourt rotation.