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Last season, Severino finished with a 102 FIP- and 0.6 WAR. This year, he’s posted a 71 FIP- and 1.7 WAR. Last year, of the 273 pitchers who pitched at least 60 innings, Severino’s 0.6 WAR ranked 186th. This year, his 1.7 WAR ranks 12th, and seventh in the American League. That’s pretty good, if you weren’t aware.
So, how did we get here? Well, various ways. A little here, a little there. One thing that’s interesting is that Severino’s success isn’t a product of him having suddenly learned how to stop fly balls from becoming home runs.