Yordan Alvarez is the best hitter in the majors this season. You might not have heard of him before a few months ago, but it’s true. He played the first 56 games of the season at Triple-A, got called up, and has now played 56 games in the majors with the Houston Astros. In that time, he’s registered 240 plate appearances, and compiled a wRC+ of 185. No one with at least 200 plate appearances this season has a better mark. Not Mike Trout. Not Cody Bellinger. Not Christian Yelich. Alvarez, a 22-year-old who was ranked just the 125th-best prospect in baseball before the season by FanGraphs, has put up more value per plate appearance than any other hitter.
Alvarez isn’t the only rookie who ranks high on that list. Peter Alonso, the Mets’ brawny first baseman, ranks ninth in the majors in wRC+. Fernando Tatis Jr., the Padres’ super-prospect who must unfortunately sit out the rest of the season due to injury, ranks 11th. Milwaukee second baseman Keston Hiura ranks 21st, and Pittsburgh outfielder Bryan Reynolds ranks 29th. If you’re not that familiar with wRC+ and prefer more common stats, the MLB’s leader in batting average this season is Twins rookie second baseman Luis Arraez (min. 200 PAs), while Reynolds is in the running for the NL batting title and Alonso is chasing the NL home run lead.
Those are just rookies who have put together season-long stretches of brilliance. We haven’t even talked about Mike Yastrzemski’s three-homer game, or the nine homers Austin Riley hit in his first 17 games in the majors. Hell, we haven’t talked about Aristides Aquino going on the greatest home run tear to start a career in baseball history. Indeed, these are wonderful times to be a rookie breaking into Major League Baseball. So why haven’t those wonderful times come for Nick Senzel?
Senzel, 24, made his major league debut with the Reds on May 3, in a nightmare game against the San Francisco Giants in which Cincinnati blew a 10-3 lead after five innings. In that game, he went 1-for-5 with a pair of walks, with the 34 pitches he saw being the highest total of any hitter in the game. Over his next three games, he hit three home runs. His first week showed a patient approach, good eye for the strike zone, and legitimate power. But that quick start didn’t last long.
This is a difficult thing to write, because it would be a stretch to say Senzel has been a disappointment. After 89 games, he’s hitting .264/.320/.436, with 10 homers and 12 stolen bases in 16 attempts. His wRC+ of 92 is below league average, as is his 7.3% walk rate, but not dramatically so in either case. In most seasons, this would be a fine debut for a rookie, particularly a center fielder. All you can expect from a young player is to hold his own and not look overmatched the first time they see big league pitching, and Senzel hasn’t. But as you can tell, this is no ordinary year for rookies. His wRC+ ranks 21st among all rookies with at least 200 PAs, and his 0.7 fWAR is 28th, behind the likes of Austin Nola, Luis Rengifo, and teammate Josh VanMeter. Only so much can be expected of rookies, but there are an awful lot of them who have done more than Senzel so far.
That’s an unwelcome development for a player who so many had such high hopes for entering this season. The No. 2 overall pick in 2016, Senzel has had some issues staying on the field thanks to a freak broken finger and some even stranger bouts with vertigo. But when he has been on the field, he’s done nothing but rake. After his 10-game tryout with rookie league Billings after getting drafted, Senzel didn’t post a wRC+ under 147 at any level between 2017-18 as he soared through the Reds’ farm system. FanGraphs ranked him as the seventh-best prospect in baseball entering 2019, the second-straight season in which he was a consensus top-10 prospect. If anyone was going to hit the ground running after getting called up to the majors, it was going to be Senzel.
So, why hasn’t he? For starters, despite having a reputation squaring up the baseball routinely in the minors, he hasn’t hit the ball very hard against big league pitching. He ranks in just the 26th percentile in exit velocity, according to Statcast, while ranking in the 31st percentile in xSLG and 24th percentile in xwOBA. When it comes to having lackluster offensive numbers, it isn’t because of bad luck. Senzel simply hasn’t been making great contact.
One cause for that may be the frequency with which he hits the ball on the ground. Out of all big leaguers with 200 PAs, Senzel has the 54th-highest percentage of groundballs, at 48.6%. That’s far from enough to prohibit good offensive numbers — Javier Baez and Shohei Ohtani have slightly higher groundball rates, for example — but still probably too high for Senzel to get the most out of his swing. He has some pop in his bat, so getting the ball in the air more would likely lead to better production.
Senzel also has a glaring weakness against sliders. According to FanGraphs’ pitch weights, he has a -4.9 wSL this season, while Pitch Info grades him even worse, at -6.1. In 58 PAs ending on the pitch, Senzel is hitting .143/.155/.232 with just one walk and 19 strikeouts this season. According to Statcast, the .230 xwOBA he’s put up against the slider is his second worst of any pitch, just ahead of the .228 xwOBA he has against cutters, which are similar pitches. Those are bleak numbers, but they’re also not entirely unexpected. Major League sliders are much different from those you see in the minors. If Senzel has this much trouble against one specific pitch, he can spend the offseason learning how better to hit it. There are plenty of examples of players who struggle with recognizing a certain pitch when they first break into the majors, only to master it later. If Senzel can do that, he’ll have eliminated an easy go-to pitch for opposing pitchers.
Overall, the outlook for Senzel is a bit of a head-scratcher. He hasn’t had a great season at the plate, but we also know that’s only part of his story. He entered this season after taking significant time off, never seeing a plate appearance after the aforementioned finger injury that shut his season down on June 22 last year. Then, in spring training, he suffered an ankle injury that forced him to miss even more time at the beginning of this year. And on top of that, he’s had to learn how to play center field — one of the most demanding positions, and one Senzel had never played before — on the fly throughout this year. His bat hasn’t metabolized quickly, but there’s a good chance it hasn’t been his primary focus for much of this season. And even then, it isn’t as though this season has been one long slump for Senzel. He entered the month of August hitting .285/.346/.475.
This month, though, has gone terribly for him. He’s hitting .189/.221/.297, with 20 strikeouts and just two walks in 80 plate appearances. That is a brutal stretch, particularly from a plate discipline perspective. Lots of slumps involve a hitter’s luck simply running dry for a couple of weeks, or an uncharacteristically low portion of flyballs leaving the yard. This has been something else entirely.
Could that turn around in time for Senzel to finish the season strong? Certainly. But after 89 games, there’s still an uncomfortable set of basic questions we just aren’t sure of. We don’t know how hard he’s capable of hitting the ball, and if the answer is “not very,” whether he can walk enough to make up for it. Those are the questions that will decide the ceiling for a player the Reds are going to rely upon for years to come.
Senzel hasn’t shown he can be a franchise-altering player yet, and that’s okay. He’s still quite young, and the circumstances surrounding his rookie season have been anything but ordinary. He also hasn’t shown signs of being a bust, which is probably a big deal as well. He’s been fine. No more, no less, just fine. Whether that’s a positive or negative is just going to depend upon the lens you’re looking through.