Yuli Gurriel, Ageless Wonder by Owen McGrattan July 2, 2021 The Astros are good. Whatever you might’ve thought of their depth after losing George Springer, there was still such an overabundance of talent in their lineup as to patch up whatever variance you could imagine with any individual player. Alex Bregman is the only non-catching starter to be trailing his projected wRC+ by 10 or more points, and he’s still holding a 119 wRC+ this year. Maybe as expected, Carlos Correa and Jose Altuve lead the team in WAR, but coming in third is ageless Yuli Gurriel. In his age-37 season, Gurriel is running a career-best 147 wRC+ and is one of only four qualified batters to have more walks than strikeouts (all stats for the rest of the piece are through June 29). It’s such an aesthetically pleasing statistical line, especially in this strikeout era, and is a step forward even for someone like Gurriel who has seldom struck out. Yuli Gurriel Plate Discipline (2016-21) Season BB% K% SwStr% 2016 3.6% 8.8% 8.7% 2017 3.9% 11.0% 8.1% 2018 4.0% 11.0% 7.0% 2019 6.0% 10.6% 6.8% 2020 5.2% 11.7% 6.7% 2021 11.2% 8.9% 4.8% Gains in plate discipline are happening under the hood as well, which is surprising given both the type of hitter Gurriel has been and the fact that this is coming from a 37-year-old. Gurriel has never been one to strikeout or walk too much, so shifts in his plate discipline can certainly fly under the radar, or they had at least to me. But in his sixth year in the majors, we can see rather clear evolutions in his plate discipline that feel more purposeful than pure happenstance. Yuli Gurriel Plate Discipline Continued (2016-21) Season O-Swing% Z-Swing% Swing% 2016 40.7% 75.5% 55.4% 2017 32.8% 67.9% 48.2% 2018 37.1% 69.2% 50.2% 2019 35.4% 69.3% 49.7% 2020 37.8% 65.9% 48.8% 2021 29.4% 64.1% 43.2% That drop in O-Swing% from 2020-21 is the fourth largest year-to-year drop among players in their age-32 or older season. The continued drops in Swing% and Z-Swing% also tell us that there’s a higher degree of selectivity going on. Given how well he can make contact, Gurriel wasn’t necessarily making poor swing decisions, but he’s found avenues by which to refine his approach. It can be hard to point to any real declines in his skill or abilities as a player at this age, especially considering he’s currently sporting the highest average exit velocity of his career by nearly 2 mph and logged his third highest max exit velocity of his career just last week. These are signs we’d look at for any player to measure his long-term outlook, but Gurriel is best categorized as just being a damn good hitter or the kind of guy to whom a scout might give an 80-grade hit tool. What may best exemplify this is the difference between his actual and xStats. Yuli Gurriel xStats (2016-21) Season Events AVG xBA wOBA xwOBA BABIP 2016 119 .262 .268 .292 .293 .267 2017 473 .299 .280 .344 .319 .308 2018 481 .291 .257 .323 .288 .306 2019 505 .298 .273 .364 .313 .289 2020 189 .232 .262 .281 .315 .235 2021 248 .330 .283 .389 .343 .328 In seasons where he has 500 or more at-bats, he ends up outpacing his xBA while maintaining modest BABIPs. This far into his career, what Gurriel is doing runs beyond luck, although we can still make sure that that isn’t at play. xBA uses only launch angle and exit velocity to predict the probability of a hit; what if we used spray angle as well? The version of spray angle I use is derived from the hit coordinates of batted balls, but for balls in play those are defined by when a ball is picked up by a fielder so there are going to be a few instances of inaccurate measures. Quickly training a Random Forest model on roughly 60,000 batted balls using spray angle, launch angle, exit velocity, batter stance, and shift/no shift classifications as predictive variables gives us an 86% accuracy in classifying whether a batted ball will be a hit or not. The same model that doesn’t include spray angle has an 82% accuracy, so there is something of a difference, but we’ll use the given xBA from Statcast instead of non-spray model predictions. Yuli Gurriel BA estimates (2021) Spray-Included xBA xBA BA .309 .283 .330 We still sit somewhere short of a full explanation, but we also don’t necessarily want to be able to explain every single hit. Some hits are just pure luck and nothing more. But these fluke events do not comprise a 50-point gap in batting average; perhaps they only make up something like a 20-point gap. As a sanity check, there are a few specific examples that let us know that Gurriel’s performance deserves to sit higher than his xBA or other xStats. If someone asked you what a batted ball with a low hit probability looked like, you’d probably imagine something hit directly to a fielder or something weakly hit. If I show you this, which has a spray-included hit probability of .886 and an xBA of .291: Are you going to believe that Gurriel pulling the ball was happenstance given his swing path and where the pitch was located? How about another example, this time with a spray-included hit probability of .850 and a xBA of .397: A semi-loopy breaking ball catching the inside of the plate should be pulled and this kind of pulled fly ball is going to be a hit. I bring up these differences in probabilities because this is where Gurriel perpetually beats his xStats and with how long it’s been going on, it appears more and more to be skill. The overall xBA is calculated as the average of all the xBAs, so while Gurriel does receive some kind of credit, over the long run those lower probabilities end up dragging down the xBA significantly. Where those differences arise: Gurriel’s batted balls from this year, courtesy of the sportyR package. There is not a perfect representation of hit distances here; I played with some of the scaling until things looked right. The pulled fly balls and groundballs up the middle made the most sense as batted ball events that would be more likely to be predicted as hits with spray angle. The spray angle model does view groundballs on the left side of the infield with greater pessimism but that largely applies to those that are hit directly at fielders. None of this is not a knock on the xStats. For just about any player, it’d be incredibly difficult to justify idealized batted ball spray as a skill. You don’t need a separate model to tell you there’s an underlying skill when Gurriel outpaces his xBA by 20-30 points in every full season he plays; it’s a testament to the kind of bat control he has always had. But in tandem with the ability to improve an approach this late into his career, it’s no surprise he’s likely going to post his best season by WAR and one of the best seasons ever for a 37-year-old.