The St. Louis Cardinals got a great performance this year from Joe Kelly. The right-hander put up a 2.69 ERA in 124 innings, including 15 starts. In his starts he had a 2.28 ERA, while he posted a 3.65 ERA in 37 innings in relief. Against the Pittsburgh Pirates, Kelly had a 2.53 ERA in 21.1 innings, with a 16:10 K/BB ratio. Today Kelly will go up against the Pirates in Game 3 of the NLDS.

The ERAs look great, but when you dig deeper into the advanced metrics, you'll see that Joe Kelly is a regression candidate.

On the season, Kelly has a 4.19 xFIP, which is 1.5 runs above his ERA. Out of all pitchers in the majors this year with 120+ innings pitched, Kelly has the second biggest difference between his ERA and his xFIP.

Kelly has a dominant ERA, but he hasn't been dominant on the m...

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