Jayson Tatum hurt his left knee in the third quarter vs the 76ers on Thursday.
Brad Stevens said Tatum's knee stiffened and swelled up the following morning, and the 19-year-old rookie would undergo further testing.
Tatum injured his knee during the 3rd qtr of Thursday's game, per Brad Stevens. "It stiffened up, swelled up a little bit the next morning. He’s going to have further testing done today."— Boston Celtics (@celtics) January 13, 2018
Tatum sat out of the Celtics' practice session, but no other details about the injury have been released. Stevens told reporters, "They don't think it's a big, big thing, but certainly we want to be cautious and want to know exactly what happened."