Vargas started the season in the Marlins' starting rotation, but he struggled there; in five starts, he went 1–1 with a 5.40 ERA, 20 walks, and 14 strikeouts in 23 innings. For the month of May, the Marlins moved him to the bullpen, where he gave up one run in 5 innings over his first three appearances. In his fourth appearance out of the bullpen, he allowed eight runs (seven earned) over 3 innings; the Marlins optioned him to the Triple-A Albuquerque Isotopes on May 14. Vargas started improving with Albuquerque, going 2–2 with a 4.54 ERA in seven starts and earning another promotion to the major leagues on July 6.