Carlos Martinez is a very good pitcher, regardless of his off-the-field (and on-the-field, at times) frustrations. Martinez tends to make some innings more exciting than they need to be, he has dealt with multiple arm ailments over the past few seasons — perhaps due to poor offseason training. Nevertheless, over the last five years, Martinez has never seen his ERA rise above 3.64. After starting 92 games between in three seasons from 2015-to-2017, Martinez has started only 18 games since 2018 while making 63 appearances out of the bullpen. Regardless of the role that he fills for the team in 2020, either as a starter or a reliever, Martinez could find some positivity if he dials down usage on his two-seam fastball (also known as his sinker).
In 2019, 20.8 percent of Martinez’s pitches were sinkers, which opponents worked a .375 batting average and a .411 wOBA against. This is not just a one-year flash in the pan. In 2018, Martinez allowed a .324 batting average and a .383 wOBA versus the pitch; in 2017, a .341 batting average and a .377 wOBA; in 2016, a .284 batting average and a .335 wOBA. Martinez’s sinker has definitely been easier for hitters to do something with, to the point where he using it is not in his best interest. This is especially true when considering how dominant Martinez has been with his changeup and his slider.
The 28-year-old’s changeup was nearly unhittable last season (.111 BA, .157 wOBA, 37.9 Whiff%) and has been a very successful pitch in the last three seasons overall. Martinez has improved his results with the pitch every year since 2016, when he allowed a .319 wOBA against. His slider was just as dominant this season, as he allowed just a .102 batting average and a .138 wOBA versus the breaker while generating whiffs on nearly 41 percent of his sliders. Since Statcast began registering his slider (not a curveball) in 2017, Martinez has not allowed a batting average over .200 on the pitch.
It appears that Martinez and the Cardinals have noticed the lack of results from his two-seamer as well. This was the first season since 2015 that Martinez threw his two-seamer less than 25% of the time. It has been a staple pitch for much of Martinez’s career, but he needs to adapt in order to improve his production, especially if he flips back to the rotation in 2020.
If the sinker is not working then it should not be thrown — or at least thrown in careful moderation. Martinez would likely see better results if he threw more sliders, changeups and four-seamers and fewer two-seamers, although there is a case to be made that this would likely decrease the effectiveness of his other offspeed pitches
It is worth noting that Martinez’s two-seam fastball is about two MPH slower than his four-seam fastball. His four-seam fastball velocity of 96.6 MPH (86th percentile) would seem a bit more overpowering when thrown after a changeup or a slider than a two-seamer. It might also help Martinez to get hitters off balance with offspeed arsenal, since there would be a wider gap in speeds.
If Martinez threw his offspeed pitches more in general, he might experience even better results. These pitches (changeup and slider) were so dominant that they could likely handle a significant increase in usage. If these pitches combined to accumulate more than half of all the pitches that Martinez throws, his near-elite fastball velocity could prove to be difficult to handle, and his pitch mix could prevent the hitter from getting comfortable in the box.
Essentially it comes down to the question: should a pitcher keep throwing a pitch (especially at such a high percentage) if it is not working? Correspondingly, should a pitcher throw more of the pitches that are dominant?
The answer to these questions seem clear. A pitcher should not keep throwing a pitch that is getting hit and he should throw pitches that hitters struggle with. Martinez’s two offspeed pitches have been so dominant that they should be able to get him through 6 or 7 innings when complemented with a four-seam fastball, if he returns to the rotation. These three pitches should be good enough to keep hitters off balance for the entirety of a start, so he should not worry about becoming predictable — even if he tucks the two-seamer deep in his pocket.
Regardless of what happens, Martinez is a good pitcher, and it seems that there is a legitimate chance for him to become a great pitcher with just a few arsenal tweaks.