It’s been almost a month since the Mariners signed Juan Nicasio to a two-year contract during the height of the MLB Winter Meetings. Since then, Jerry Dipoto hasn’t done much of anything else. It’s been a weird offseason. Back to Nicasio. Last year was definitely a breakout season for him despite being on the wrong side of 30. Without much else to talk about, let’s take a deeper look at the newest member of the relief corps.
Nicasio got his start in the Rockies organization as a starter but moved to the bullpen partway through the 2014 season. With just a fastball and a slider as his primary pitches, it’s no surprise he found himself in the bullpen sooner or later. He’s flourished in shorter appearances, lowering his FIP by more than a run and a half and accumulating 3.7 fWAR over the last three seasons as a reliever. But with his fastball-slider combo, he’s suffered a pretty significant platoon split throughout his career.
Between 2014 and 2016, left-handed batters posted a .395 wOBA against Nicasio. He was able to keep right-handed batters in check but lefties torched him. Last year, left-handed batters posted a .235 wOBA against him, a mark lower than what righties were able to accomplish. He flipped his platoon split, and that, more than anything, drove his breakout season.
One of the concepts Jerry Dipoto has been preaching during his excellent podcast series has been effective velocity. Rather than perceived velocity, which can be calculated using arm extension and a pitcher’s release point, effective velocity measures reaction time gained or lost based on the location of a given pitch. It can help us figure out how much more time a batter has to react to a pitch on the outside corner versus a pitch up and in. Generally, a batter has more time to react to a pitch low and away than they do to a pitch up and in.
We’ve seen a number of Mariners pitchers working effectively in the upper quadrant of the strike zone (Nick Vincent is the poster child). Between 2016 and 2017, Juan Nicasio changed his approach specifically against left-handed batters. Below are two heatmaps showing the pitch location of Nicasio’s fastballs against left-handed batters from 2016 and 2017.
When he moved to the bullpen, he added a couple of ticks to the average velocity of his fastball. That’s certainly made it a better pitch but where he’s locating it has a lot of influence too. In 2016, he mostly kept his fastball away from left-handed batters. He stayed away from lefties for the most part in 2017 too, but there’s also that cluster of pitches up and in that wasn’t there in 2016. He didn’t see an increase in whiffs off his fastball but the change in location severely limited the contact opposing batters were able to make off him. In 2016, left-handed batters posted a .341 xwOBA off his fastball. He dropped that mark to just .212 in 2017. He found the confidence to pitch in those deadly locations more often and that helped him flip his platoon split.
That newfound confidence most likely stems from much better command of his pitches. He posted the second lowest walk rate of his career last year and pitched in the zone at the second highest rate of his career. The combination of better command, a better understanding of how to keep hitters off-balance, and a deadly combination of pitches helped him thrive despite bouncing between three different teams. With the Mariners focused on maximizing the repertoires of their pitchers by any means necessary, I think Nicasio will fit in nicely in Seattle.