Going into 2023, the Pittsburgh Pirates will have one of, if not baseball's most underrated starting pitching duos between Mitch Keller and Roansy Contreras.
The Pittsburgh Pirates are entering the 2023 season with questions in the rotation's back half. With the trio of Johan Oviedo, JT Brubaker, and Vince Velasquez and just two rotation spots, the Pirates are going to need to figure out the back half. But they signed Rich Hill as a veteran rotation anchor and have two young players atop their starting five. That's Mitch Keller and Roansy Contreras, who might be baseball's most underrated starting pitching duo.
Keller's breakout might have just been one of the least talked about things across baseball last year. 2022 was a massive make-or-break season for Mitch. After some extremely odd seasons, such as in 2019 when he had a .475 batting average on balls in play, then in 2020 when he had a .104 BABIP, both of which were record-setting numbers, and then a terrible 2021, the future was extremely uncertain for the former right-hander. At one point, it looked like a break season for Keller, as by mid-May, he was moved to a bullpen role.
But then something for Keller clicked. He added a sinker to his arsenal, and things started to work out heavily in his favor. After significantly incorporating this new pitch into his arsenal on May 25th, Keller would go on to work to the tune of a 3.20 ERA, 3.67 FIP, and 1.35 WHIP through his next 123.2 innings of work. While Keller only struck out 20.5% of the opponents he faced, he also had a solid 8.7% walk rate. Keller became a heavy ground ball pitcher, inducing a ground ball at a 49.9% rate, which helped him have a 0.65 HR/9. He ended the season in the 63rd percentile of opponent exit velocity and 56th percentile of opponent hard-hit rate, making his ground ball rate even more productive.
Keller was a top-15 pitcher in the National League during this stretch. Among pitchers with 110+ IP, from May 25th onward, Keller ranked 15th in ERA, 19th in FIP, and 9th in HR/9. He wasn't particularly looked fondly upon by WHIP, but who isn't going to take a low-3.00 ERA/mid-3.00 FIP pitcher in their rotation?
Then, on the other hand, you have Roansy Contreras. Contreras was considered a consensus top-100 prospect heading into the 2022 campaign, and he delivered some decent results. In 95 innings, Contreras had a 3.79 ERA, 4.48 FIP, and 1.24 WHIP. Contreras had a 21.1% strikeout rate, 9.6% walk rate, and 1.23 HR/9, which is fairly unimpressive on paper. However, one start did inflate his numbers, that being on July 1st where he gave up seven earned runs on three home runs in just 1.2 innings. Outside of this one tanked start, Contreras had a much better-looking 3.18 ERA, 0.94 HR/9, a 21.5% strikeout rate, and a 9.3% walk rate.
Contreras also had a much higher strikeout rate in the minor leagues. At Triple-A, he struck out 33.1% of opponents faced, albeit in just 38 innings. But if you combine his innings from Altoona and Indy, a total of 92 frames, he still had an outstanding 34.1% mark. He was also in the 64th percentile of chase rate and 82nd percentile of whiff rate, showing that there could be an increase in strikeout rate. Shane Bieber had similar remarks in the two stats, as did Luis Castillo, and both had a strikeout rate of at least 25%.
As the Pirates head into 2023, having Mitch Keller and Roansy Contreras head the rotation will be fun to watch. The only team that makes a strong case in the National League Central for a better 1-2 is the Milwaukee Brewers. It shouldn't surprise any Pirates fans that by the end of the year, both Contreras and Keller are two of the more notable pitchers, not just in the National League Central or National League, but all of MLB.