Esteury Ruiz and Finding Slugging in Speed

On Sunday in Oakland, with the A’s trailing the Phillies 3-1 and lefty José Alvarado on the mound, A’s manager Mark Kotsay sent the right-handed Esteury Ruiz to the plate to pinch hit for lefty Seth Brown, hoping to use a platoon advantage to mobilize some sort of comeback. After falling behind 1-2, Ruiz turned on an Alvarado cutter and sent a 94.1-mph grounder past the third baseman and into left field, giving his team some hope:

Ruiz would come around on a Carlos Pérez single, but the rally would ultimately fall short as the A’s extended a losing streak that has since run to eight games. But Ruiz had done all he was given the chance to do.

It was Ruiz’s third double in as many games and his 18th of the season, and it looked familiar. The rookie outfielder has made a habit of dumping batted balls down the baselines, giving himself a chance to use his speed to grab extra bases. Here’s a spray chart of those 18 doubles:

I find this spray chart amazing. Of his 18 doubles, 16 have gone down one baseline or the other, with 11 headed to the pull side and another five landing within feet of the right field line. Just two have bucked the trend and landed in the other maybe 85 radial degrees of available fair territory: a gapper in Houston that he only managed to stretch into two with the help of a swim-move slide (and video replay), and a 381-foot blast into the extended outfield in Baltimore that would’ve been one of two home runs on the season in 21 out of 30 ballparks. Ruiz has an average hit distance of just 160 feet on his doubles, the shortest average out of 167 major leaguers with at least 10 doubles this season – just three other hitters are averaging less than 200 feet on doubles.

To put it bluntly, Ruiz needs every extra point of slugging percentage he can find. Almost halfway into his rookie season, Ruiz is last among qualifiers in average exit velocity with a mark of 83.2 mph, a full tick lower than the next-lowest figure. His 20.0% hard-hit rate is also the lowest in baseball, while his barrel rate, xSLG, and xwOBA are all in the bottom 5%. He’s been an extreme groundball hitter so far this year, putting 50.6% of his batted balls on the ground and just 28.9% in the air. As far as power goes, he’s among the lightest hitters in the league. With that kind of batted-ball profile, you have to find other ways to generate value.

Of course, Ruiz primarily makes a living with his legs. He leads the big leagues with 39 stolen bases in just 75 games, putting him on pace – thanks in part to the Big Bases – to become the first player to swipe 80 bases since Rickey Henderson and Vince Coleman both did so in 1988. His 29.8 mph sprint speed is in the 98th percentile, and his 6.2 baserunning runs above average (BsR) trail only Corbin Carroll for the major-league lead. He’s the type of player who impacts games with his speed in a variety of ways:

One of those ways – which isn’t accounted for by BsR – is by stretching singles into doubles, and Ruiz is able to make up some of what he lacks in power by turning a handful of baseline grounders and soft liners into doubles. This isn’t unique to Ruiz, of course – he didn’t exactly invent the down-the-line double – but I would argue that it’s a uniquely important part of his offensive production given how infrequently he gets a hit over an outfielder’s head or through the gap. Although BsR won’t account for this added value, slugging will.

One way to illustrate how speed could have an impact here is by considering the “surplus” value on Ruiz’s doubles. His 18 doubles have had an average xSLG of .584. Because slugging percentage is just total bases per at-bat, all doubles have a SLG of 2.000, meaning Ruiz has gotten 1.416 more points of slugging percentage than would’ve been expected on those 18 batted balls. That’s the second-highest difference among those same 167 hitters with 10-plus doubles. There are a whole bunch of factors that go into the expected slugging values of those batted balls, but it’s certainly conceivable that Ruiz’s speed is helping him turn more batted balls into doubles that Statcast would expect to be an out or a single:

Those 18 hits are contributing to the difference between a .317 xSLG and .278 xwOBA – both in the bottom 5% of the league – and a .343 SLG and .298 wOBA, which, despite not being very good in their own right, are a good bit higher than expected, and enough that with his baserunning value as high as it is, Ruiz has been worth 1.2 WAR in 75 games. Ruiz is so productive a baserunner that even with a .298 wOBA – 135th out of 158 qualifiers – and below-average fielding in the outfield, he could be an above-average major league producer.

If sneaking hits past the third baseman is a big part of Ruiz’s recipe for generating extra-base hits, he appears to have the right swing to do it:

Ruiz is driving a ton of groundballs and line drives to the pull side. That’s a dangerous recipe, but has thus far led to a .266 batting average and given him plenty of opportunity for singles to turn into doubles. Some 44% of his groundballs and line drives go towards left (compared to just 12% of his fly balls), and the harder he hits it, the more concentrated to that hot corner they seem to get. Here’s the same spray chart, but only for balls hit at 100 mph or harder:

Ruiz has fared better than most on these pull-side grounders. Among 134 right-handed hitters with at least 25 groundballs to the pull side, Ruiz’s .302 wOBA – which is higher than his overall mark – ranks 18th. On line drives to the pull side – where 41.7% of his line drives have gone – he has a 1.100 SLG and an .819 wOBA.

The main challenge of being a player that leads with his legs is that you have to do enough at the plate to get opportunities to generate value as a baserunner (or batter-runner, even). While Ruiz is winning that battle right now, it can be a delicate titration. In 2022, Ruiz was an on-base machine at the upper levels of the minors between the Padres and Brewers organizations, but that ability has yet to translate to the majors, where he’s walking at a meager 3.9% clip. With the type of baserunner he is, there’s a sort of amplifying effect on the ability to get on base – the more times on base, the more value he generates and the more opportunity he creates for more value generation.

It’s early in his career, and while there’s much to learn from his almost 250 batted balls this year, we could certainly see some of his patterns shift as he settles in. I lean towards thinking that grounding the ball to the left side as often as Ruiz does may not be a sustainable way to produce. But for a player on the opposite extremes of speed and power, it might take an unorthodox approach to stick in the majors. So far, Ruiz is making it work.