Financial terms of the deal were not disclosed.
The Memphis Grizzlies waived Bell in March after two games. He also appeared in 27 contests for the Minnesota Timberwolves during the campaign and averaged a combined 3.2 points and 2.8 rebounds in 8.8 minutes per game.
Bell was eligible to sign only with any of the eight eliminated teams since he was waived after March 1, according to ESPN's Bobby Marks.
Cleveland also converted forward Dean Wade's two-way contract into a multi-year deal on Monday, sources told ESPN's Adrian Wojnarowski.