After being the "workhorse" of the Triple-A Lehigh Valley Iron Pigs, Martin was called up to the major leagues to make his debut against the Atlanta Braves on August 2, 2013. He allowed 6 runs in 4 1/3 innings to take the loss in his debut. Martin earned his first Major League victory on August 8, 2013 with a 12-1 victory over the Cubs. He allowed one run over 5 innings. After seven starts in which he amassed a 2–4 record with a 6.90 ERA, Martin was sent to the bullpen. At that time, Phillies veteran pitcher Roy Halladay gave him a baseball card that showed the 2000 season in which Halladay posted a 10.64 ERA, encouraging Martin to understand even the best pitchers have rough spots.
Entering spring training in 2014, Martin was in major league camp, and was expected to compete for a spot on the major league roster, either as a starter or a reliever, however he left his first spring training appearance due to discomfort in his throwing shoulder – though in 2013 his fastball averaged 93.2 miles per hour (150.0 km/h), it reached only 85 miles per hour (137 km/h) during the appearance.