Mota was called up to the Expos on May 2 to replace relief pitcher Shayne Bennett, who had been demoted to Ottawa after struggling in his first four games. Mota made his major league debut the same day, pitching a scoreless inning in an 8–7 loss to the St. Louis Cardinals. He got his first major league decision on May 11, when, after pitching scoreless innings, he gave up a walk-off home run in the tenth inning to Luis Gonzalez in a 4–3 loss to the Arizona Diamondbacks. On June 1, he won his first major league game, also against Arizona after pitching three scoreless innings in the Expos' 10–8 victory on June 1. On June 9, he hit a three-run home run in his first major league at bat (against Mark Guthrie) in a 13–1 victory over the Boston Red Sox. On August 29, he allowed one run in one inning and was the winning pitcher in an 8–6 victory over the Cincinnati Reds. The win (the Expos' eighteenth in August) set a new Expos' record for wins in a month. Mota had a 1.49 ERA over his first 32 games of the year, but a 15.00 ERA over his next six games brought his ERA for the season to 3.40. However, he collected a 1.38 ERA over his final 12 games to bring his ERA for the season down to 2.93, and he finished the year with a 2–4 record in 51 games.