The deal is nonguaranteed, Scotto added, indicating Watanabe will have to make the final roster for the deal to kick in.
Watanabe, 27, is 6-foot-9 and has spent time with the Grizzlies and Raptors since going undrafted out of George Washington in 2018. Last season, he averaged 4.3 points and 2.4 rebounds in 38 appearances with the Raptors.
He hails from Japan and will become the first Asian player to sign with the Nets since Joe Tsai has owned the franchise.
The Nets still have three Exhibit 10 contract slots available, as well as one standard contract spot, as noted by Brian Lewis of the New York Post.