After leaving the Toyota Alvark in 2003, Tabuse became the first Japanese national to play in the NBA's summer league, playing six games in the Rocky Mountain Revue for the Dallas Mavericks, averaging 4.5 points, 1.7 rebounds and 1.0 assists in 13 minutes per game. Tabuse's first attempt at making it to the NBA made the headlines in Japan, and drew large media attention. On September 27 of that year, Tabuse joined the Denver Nuggets' training camp, but he was waived on October 24, before the start of the regular season.