Prior to this, Watanabe was signed to a two-way contract with the team, which he inked on Dec. 20, 2020. Terms of the deal were not disclosed per team policy.
Watanabe, 26, is averaging 4.0 points, 3.3 rebounds and 13.4 minutes in 39 games so far this season. He has started once this season and is shooting 44.8 per cent from the field.
A native of Japan, Watanabe recorded a career-high 21 points on April 16 against the Orlando Magic.
Previously undrafted, the 26-year-old spent the last two seasons as a two-way player with the Memphis Grizzlies before joining the Raptors.