Bell made his major league debut against the Tampa Bay Rays on August 12, 2009, at Angel Stadium of Anaheim. He went 51⁄3 innings, giving up four runs on nine hits and one walk, striking out four. He received a no decision as the Angels were behind by two runs when he left the game. He earned his first major league win in his second start on August 18, 2009 against the Cleveland Indians, going 51⁄3 innings, giving up three runs on nine hits and two walks, striking out two.
Bell was signed to a minor league deal with the Cincinnati Reds on May 20, 2013. He pitched for the Reds in spring training 2014 as a non-roster invitee. On March 29, Reds manager Bryan Price announced that Bell had made the Reds' opening day 25-man roster.