Then, during a May start in Arizona, his quick start came unraveled. Vargas was removed in the second inning after allowing seven runs and experiencing a decline in velocity. A day later, news came down that Vargas had suffered a flexor strain in his right elbow. He would miss the final four months of the season.
For the first time since, the 25-year-old right-hander was back on the mound pitching for the Padres on Saturday. He entered in the third inning of the Cactus League opener and tossed two scoreless frames in a 13-3 loss to the Mariners.
"No pitcher wants to get hurt," Vargas said through a team interpreter. "But at the same time, every experience teaches you something. You learn from everything that happens. There's a maturation process. I'm going to work hard, and people who have the power of making decisions know what I can do."
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Vargas struck out three Mariners on Saturday, showing off his signature pitch in the process. He froze Mariners slugger Nelson Cruz with a late-breaking cutter that trailed over the inside corner.
Well, we can call it a cutter, at least. Vargas doesn't -- because he doesn't do anything particularly special to the pitch.
"That's just his four-seamer," said catcher Christian Bethancourt. "His ball just naturally cuts. He doesn't really have a straight pitch. [As a catcher] I like that. Hitters don't."
Cutter, fastball, whatever it is -- it baffled big league batters from the start. Vargas became only the second pitcher in Padres history to begin his career with three consecutive starts in which he allowed one run or fewer. Before his blowup in Arizona, he had posted a 3.34 ERA.
Vargas -- who is one of about seven pitchers in the mix for the final two rotation spots -- fully recovered early in the offseason. He made 10 relief appearances for Hermosillo in his native Mexico and posted a 1.98 ERA.
He's only made one Cactus League appearance, but it appears as though Vargas has carried that success with him.
"I'm sure it was difficult for him to be that close to securing a long-term spot in a big league rotation based on the way he was throwing the baseball," said Padres manager Andy Green. "He gets hurt and misses the rest of the year, I know that was tough.
"But we'll find out how resilient he is this year, and he'll have the opportunity to prove and fight for that job."