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Medina, 19, recorded four strikeouts and generated another 13 outs on the ground, throwing 60 of his 99 pitches for strikes. He issued one walk and hit a pair of batters in the outing.
"He just mixed his pitches," Crosscutters pitching coach Hector Berrios told MiLB.com. "He knew that this team came out swinging a lot at the fastball in the first two games, and he took advantage of that. He threw his share of fastballs too, but he once he set the tone with that, he used his off-speed pitches to great effect."
Medina opened the game by tossing three flawless innings before an infield error to begin the following frame ended his bid for a perfect game. The right-hander then retired 15 of the next 18 hitters he faced before surrendering the ninth-inning single.
Medina has yet to allow an earned run in three starts for Williamsport this season, and he's given up six hits in 21 innings in that span.
In his 2015 U.S. debut, Medina, whom the Phillies signed out of the Dominican Republic in May 2014, opened eyes by posting a 2.98 ERA over 45 1/3 innings (10 appearances/8 starts) for the club's affiliate in the Rookie Gulf Coast League.
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.