Boston Celtics rookie Tremont Waters suffered a concussion and has yet to clear concussion protocol, C's head coach Brad Stevens announced on Monday.

“Tremont has a concussion from three or four days ago, so he’s at the latter stages of concussion protocol with his stuff, but he hasn’t been cleared,” Stevens told reporters on a Zoom call.

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Waters, a second-round pick in the 2019 NBA Draft, signed a two-way contract with the C's last summer and was sensational for the Maine Red Claws. The 22-year-old averaged 18 points, 7.3 assists and 1.9 steals per game while earning the G League Rookie of the Year award and finishing third in the G League MVP race.

In 10 games with Boston, Waters averaged 3.3 points and 1.2 assists.

Waters isn't the only Celtics guard recovering from injury, as Kemba Walker continues to recover from a bothersome left knee.

The C's season restart is set to begin July 31 vs. the Milwaukee Bucks.