Is It Legit? Mike Foltynewicz's Breakout

We're still going strong with another preseason edition of "Is It Legit?" to discuss a surprising breakout performer from the 2018 MLB season in order to assess his value heading into 2019.

With so many players seemingly becoming fantasy baseball darlings overnight, it can be challenging to sift through the multiple hype trains and determine which players are actually expected to produce similar, or even better, numbers the following year.

After three straight subpar seasons with an ERA over 4.30 and a K% below 21.1, Braves right-hander Mike Foltynewicz broke out in a big way in 2018. The 27-year-old posted a 2.85 ERA, 1.08 WHIP and a 27.2% k rate, while making 31 starts and going 13-10. Is that kind of production sustainable looking into 2019, or was he a one-year wonder?

No More Tinkering

Similar to Trevor Bauer's adjustments, it seems like Folty finally found a pitch-mix that actually works for him. Gone is his atrocious sinker, instead being replaced by a much sharper four-seam fastball. The biggest change, however, was a big increase in his slider usage. This pitch was straight nasty last season, posting a 40% o-swing rate and an 18% swinging strike rate, while seeing an increase from 21% usage to 27%.

Folty was more willing to use the pitch later in counts, something he had been unwilling to do previously. That allowed him to play it off his (improved) fastball, getting more swings and misses and overall better results.

While improvements to his fastball and slider are huge, and help explain the 1+ ERA difference from last season, there's definitely more to the story.

A Few Points of Concern

Folty's fastball and slider make up a good chunk of his pitch repertoire, but a lot of signs point to his other secondaries, a show-me curveball and a flimsy changeup, not holding up as well as they did last year.

His curveball is a "show-me" pitch. It hit the zone over 45% of the time last season, and generated very few chases out of the strike zone. It benefited greatly from a .216 BABIP, results that seem unlikely to repeat themselves if he doesn't make any changes to how he uses this offering.

Likewise his changeup routinely posted less than stellar swinging strike numbers, with a sub-15% swinging strike rate and a 21% o-swing rate last season. Unlike the curveball, Folty isn't even very good at locating this pitch, with a zone rate below 40%. He doesn't have much confidence in this pitch later in the count, and therefore it is seldom used.

Lastly, a cursory look at Folty's numbers show reason to believe some regression is coming. His 2.85 ERA was 'supported' by a 3.37 FIP and a 3.77 SIERA. He had some luck on his side, as evidenced by his .251 BABIP (career .303) and 9.6% HR/FB rate (career 11.7).

Overall, Folty is somewhere in between his very stellar 2018 numbers and the subpar three seasons he put together previously. The noticeable changes to his fastball and slider should stick, but regression on his other secondaries, not to mention a return to form on his HR/FB rate, should land him with an ERA closer to the mid-3.00's and a WHIP around 1.15 - with a K rate around 25%.

That still holds a lot of value, and I'm more than comfortable ranking him as a top-30 starting pitcher next season. While I think his current ADP (79 on Fantrax) is too high, I am comfortable with him in the 105-115 range if you are willing to bet that his two-pitch mix is nasty enough to withstand some regression on the curveball and changeup.

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