Is it Legit? German Marquez's 2018 Breakout

We continue with our next edition of "Is It Legit?" to discuss another 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.

23-year-old right-hander German Marquez broke out in a big way for the Rockies last season, making 33 starts and posting a 3.77 ERA with a 1.20 WHIP and a staggering 230 strikeouts. Is his performance indicative of his future ace potential, or is he the next Rockies pitcher to flame out after one good season?

Can Marquez Repeat in 2019?

It was a tale of two halves for Marquez last season. In the first half, Marquez posted a 4.81 ERA, a 1.39 WHIP and a 9.26 K/9. Those numbers had him on the waiver wire in most fantasy formats, and for good reason. However, he really turned things on in the second half, posting an excellent 2.61 ERA with a 1.00 WHIP and a ridiculous 12.00 K/9. In fact, from July 29 until September 26, Marquez racked up 12 consecutive quality starts, posting nine or more strikeouts in eight of them. It was one of the hottest pitching streaks in all of baseball and won a lot of fantasy owners their league.

So what can we expect from the 23-year-old flamethrower in 2019? Is he the stud second half pitcher who is no doubt ace material, or is he the streaky, homer-prone starter from the first half?

First, a look at what changes Marquez made to improve his numbers so dramatically. His BB/9 dropped from 3.23 in the first half to 1.94 in the second. His HR/9 dropped as well, from 1.49 to 0.68. This may be a tad flukey, however, as his hard-hit rate jumped from just 34% in the first half to 41.9% in the second half - while his HR/FB rate went from 17.9% to 12.1%.

Still, assuming regression hits him in the home run department, a likely reality in Coors Field, fantasy owners will accept a few more home runs if he can keep posting 10+ strikeout games. But is that sustainable?

Perhaps the biggest change Marquez made from the first half to the second half was his pitch mix. In the first half, when he posted the 4.81 ERA and was generally unownable in fantasy, Marquez threw 57.8% fastballs, 13.4% sliders, 22.0% curveballs and 6.8% changeups. In the second half, when he flat out dominated, Marquez threw 50.5% fastballs, 20.6% sliders, 22.8% curveballs and 5.8% changeups. It doesn't take a rocket scientist to figure this one out: Marquez relied less on his heater and more on his devastating slider in the second half, and the results showed tremendous improvement in preventing runs and racking up the strikeouts.

All-in-all, Marquez's second-half numbers may be due for some slight regression thanks to an unsustainable hard-hit rate and surprisingly low HR/FB rate. However, his increased use of the slider helped him rack up ridiculous strikeout numbers - among the best in the league. As long as he keeps that slider usage up near 20%, there's no reason he can't post an ERA in the mid 3.00's and a 10.5 K/9 over a full season, which makes him a borderline top-20 starting pitcher in the entire league.

Feel comfortable looking at him in rounds 5-7, even with the dreaded Coors Field as his home ballpark. This breakout is legit, and the best may be yet to come for the young hurler.