The Chiba Jets on Tuesday said star signing Yuta Watanabe is expected to miss six weeks with a sprained left ankle after getting hurt in the second game of the team’s season-opening back-to-back against the Utsunomiya Brex. The Japanese Olympic men’s basketball team forward is playing his first season in the domestic B-League after a six-year NBA career, including stints with the Memphis Grizzlies and Toronto Raptors. He exited late in the first quarter of Chiba’s 80-61 win over Utsunomiya on Sunday at the newly opened LaLa arena Tokyo-Bay in Funabashi, Chiba Prefecture. Watanabe had 16 points…