What’s behind Julio Rodriguez’s poor performance (at least by his standards)? Three problems for the Mariners

While getting ideas for articles from social media posts should be scorned at nearly every turn, as it’s often the mark of a wayward creative spirit, we must admit we felt inspired by veteran ballwriter Rob Neyer’s tweet Tuesday night. “The Mariners are the Royals without Bobby Witt,” he tweeted, which received little response.

Our motivation had less to do with the baseline-level text of Neyer’s words (that Witt is the transformative force taking the Royals upward and forward) and more with the subtext: specifically, what it says about the player who was supposed to be the Mariners’ Witt: Julio Rodriguez, the 23-year-old who established himself as a starting center fielder. No one should forget that Rodriguez entered this season with more than double Witt’s career win total — and that’s despite appearing in 21 fewer games. Yet this season has been a disappointment, to the point that he’s going to finish with career-low marks in every notable statistic: home runs (16), steals (22), each of the triple slash line measurements, OPS+ (110), WAR (3.6), and so on. (Note, most MLB teams would be happy to have a 110 OPS+ and a nearly four-win performance from their center fielder.)

Rodriguez and the Mariners, at this stage, look more likely to miss the playoffs than make them. (They are three games behind the nearest wild-card spot on Wednesday.) Witt and the Royals, by contrast, are firmly in possession of the second wild-card spot. It’s fair to wonder where the Mariners would be right now if Rodriguez were finishing a season more akin to his more typical output.

Instead, Rodriguez and the rest of Seattle have to wonder: Where did things go wrong this year? Below, we’ve identified three factors that explain their relative step back.

1. Swing and change in approach in the offseason

One of the funny things about Rodriguez’s season is that the Mariners were convinced in the spring that he was going to have his best season ever.

The changes Rodriguez made to his swing and his approach over the winter sparked optimism. Then-manager Scott Servais, who was replaced by former catcher Dan Wilson earlier this year, told Adam Jude of the Seattle Times that a six-pitch walk by Rodriguez early in the season was “a sign of a young superstar maturing.”

Rodriguez himself said he feels he’s on the cusp of a big year after streamlining his operations.

More than six months later, it’s fair to say those changes haven’t had the desired effect — it’s even possible they’ve negatively impacted their season. We’ll discuss more about swing elements and how they manifest in later subheadings. As far as this case is concerned, let’s just say that whatever changes they tried to make didn’t work.

In fact, Rodriguez is drawing the same number of walks as last season; he’s chasing more often than he did in 2022 (though less often in 2023); and so on. Here’s a look at some of his most important plate discipline stats, including his SEAGER score — a fancy pants statistic created by Robert Orr that attempts to provide a single measure for a batter’s approach. (Note that the higher the SEAGER, the better.)

We will admit that a batsman’s approach is difficult to understand statistically, and that Rodriguez could have raised the bar in ways that don’t show up in the statistics. But, from this perspective, it seems the hype about a more mature approach was all a hoax.

Speaking of complex systems, what can be said about the changes taking place in them?

2. Worse against velocity

“You’ll start to see some differences all over the place,” Rodriguez told reporters about his revised swing during spring training. “But I think those were some of the things I tried to improve. Just making sure I don’t have too much movement. I’m a big guy, I don’t have to do a lot to be able to drive the ball.”

In theory, there is nothing wrong with a batter wanting to become more efficient. Any extraneous movement can throw a batter out of position, costing them time they can afford to waste. This can result in more foul balls, poor contact points, or even more swinging strikes; the batter may even make poor swing decisions because they feel compelled to decide in advance whether or not to offer up a pitch.

Then again, you can understand why Rodriguez and whoever instructed him in such matters might have wanted him to tighten up his rhythm a bit more.

Unfortunately, the “after” version of Rodriguez looks a lot worse than the “before” version in a few different ways, including his performance against velocity. Take a look at how his performance has declined against pitches clocked at 92 mph or above:

For those wondering, the league-average mark on pitches thrown 92 mph or faster this season is a .740 OPS. Rodriguez is still above that threshold, though not by as much of a margin given his youth (he’s not at an age where you’d expect a huge drop-off in his bat speed or rotational acceleration) and talent level.

If we’re fair to Rodriguez and his hitting coach, his decline against velocity didn’t start this season and can’t be entirely attributed to changes in his swing. He suffered a decline last season that was offset by better overall numbers. That decline — which may have been the impetus for a reworked swing and approach — has been exacerbated by further declines this year.

We believe there is another factor that helps explain Rodriguez’s declining performance.

3. Do not pull the ball again and again

We referenced “point of contact” earlier. It’s a simple measurement: where the bat actually connects in relation to the plate. It’s a piece of quantitative information that isn’t yet publicly available, but it likely influences some decisions (and the interpretation of some performance fluctuations) in the front offices of major companies.

Although we don’t have that data, we can use proxy measures to gauge when a player’s contact point has changed – whether it’s for the better or not. To our eyes, Rodriguez appears to be a case where his contact point has decreased.

That is, Rodriguez entered Wednesday with a .124 ISO (that’s slugging percentage minus batting average), a mark that puts him in the category of Steven Kwan, Anthony Volpe and other batters whose power output shouldn’t be associated with someone like Rodriguez. For reference, he came into this season with a career .216 ISO.

What’s causing Rodriguez’s power outage? You can tell by how his average exit velocity has been declining year over year, and he’s recorded a lower frequency of batted balls with exit velocities of 95 mph or above. We think this is a byproduct of the big culprit: his contact point. The surest way to slug or make hard contact is to pull the ball (especially in the air, because those are where you get extra-base hits).

Rodriguez’s bat-ball spray breakdown (courtesy of TruMedia) shows he’s pulling the ball less often than at any point earlier in his big league career. Note:

That’s a shocking year-over-year drop in pull rate. We’re not going to get too deep into philosophical entanglements. We know there are different schools of thought about how much priority batters should give to pulling the ball. But our rule is that you generally shouldn’t mess with what works unless there’s a good reason to. Given that Rodriguez had a lot of success pulling about a third of his batted balls this season, we doubt he or the Mariners intended their changes to have this kind of impact on his game.

We’re not swing doctors, so we’re not going to pretend we have a magic solution for Rodriguez. Our conclusion is that Rodriguez’s season — which, again, ranks him among the top 10 or so center fielders in the game — is a warning of how well-intentioned maintenance can have unexpected consequences.

Our hope is that Rodriguez can retool his swing this offseason, reminding people why he was at or above Witt’s level just six months ago.