Full Count: Geraldo Perdomo's breakout looks unsustainable — but he should be an All-Star

To say that Geraldo Perdomo struggled in his rookie season would be an understatement. In 2022, he hit .195/.282/.265. His .547 OPS was the lowest in baseball among hitters with 500 or more plate appearances. His 85 mph average exit velocity and 25.1 percent hard-hit rate ranked in the third and second percentiles, respectively.

This year, Perdomo’s results have taken a dramatic turn for the better. After reaching base four times in Thursday’s 5-3 win over the Washington Nationals, Perdomo is hitting .297/.406/.462 with five homers, 13 doubles and one triple. He also grades out as an above-average defender at shortstop, and he is already 9-for-11 in stolen base attempts.

Perdomo has clearly been one of the best shortstops in baseball. His .868 OPS is second among NL shortstops with 200 or more plate appearances, only behind the Atlanta Braves’ Orlando Arcia. Entering play on Thursday, Perdomo also ranked second in the National League with 2.6 fWAR, trailing only Chicago Cubs $177 million man Dansby Swanson.

What is puzzling is that, despite going from one of the least productive hitters in baseball to one of the most, Perdomo’s underlying metrics in 2023 closely resemble those of last year.

In fact, his average exit velocity has gone down, from 85 mph in 2022 to 84.9 mph this year (entering play on Thursday). His hard-hit rate had gone down as well, from 25.1 percent to 21.2 percent. According to Baseball Savant, both his expected batting average and expected slugging percentage have decreased, too.

Frankly, it doesn’t look like Perdomo can keep this up. He has made clear, tangible improvements offensively — more on those later — but his current quality of contact is more indicative of a utility player than a top-five shortstop in the sport.

Nonetheless, it is important to make a distinction between the player that Perdomo has been so far and the player we ought to expect moving forward. He has been incredible for the D-backs so far this year — full stop. He should receive serious All-Star consideration accordingly.

What Geraldo Perdomo is doing well

Diamondbacks hitting coach Joe Mather knows as well as anyone that Perdomo is not making consistent hard contact in 2023, but he does not view that as a problem.

“Hard contact isn’t necessary to win a big league ballgame or to be an everyday big league player,” Mather said. “What’s really more necessary is having a good eye, plate discipline, getting on base one way or another. Hard contact for guys who have that is just a bonus.”

Perdomo is the most disciplined hitter on the Diamondbacks, swinging at just 16.9 percent of pitches out of the zone. That is down from 20.5 percent last year. Entering play on Thursday, his 16.9 percent chase rate was tied with Juan Soto as the third lowest mark in baseball.

When Perdomo does chase out of the zone, he still makes contact 68.1 percent of the time. That ranks in the top 30 in baseball among players with 200 or more plate appearances. Perdomo rarely swings at bad pitches; when he does, he often makes contact anyway.

As would be expected, the D-backs’ 23-year-old shortstop is great at drawing walks and avoiding strikeouts. His walk and strikeout rates of 14 and 17.2 percent, respectively, are both excellent.

Unfortunately, not all selective hitters are able to do damage on hittable pitches, and that has certainly been the case for Perdomo. On top of his poor average exit velocity and hard-hit rate, Perdomo’s 2.1 percent barrel rate — a barrel is essentially an ideal batted ball — ranks in just the third percentile.

Perdomo is not making much ideal contact, but, granted, a hit is a hit.

“We certainly don’t discriminate on how hard we’re hitting our hits,” Mather said. “We’re gonna take them all. And to his credit, he’s hitting a lot of balls on the line. So, those balls are going to drop no matter how hard you hit him.”

While many of Perdomo’s batted ball metrics have hung steady or even worsened from last year, he has increased his line drive drive from 21.1 percent last year to 25.3 percent this year. League average is 24.9 percent.

Line drives are great for any hitter, but especially for Perdomo. Say, for example, that he hits a ground ball or fly ball with a 78 mph exit velocity. In the majors, that is practically an automatic out. It gives defenders too much time to react.

If he hits a line drive at 78 mph, however, it often will look something like this:

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Put simply, Perdomo succeeds when he hits line drives. Any other type of batted ball — especially a fly ball — is bad news.

The graph below shows 15-game rolling averages for Perdomo’s line drive rate and wRC+ in 2023. (wRC+ is an all-encompassing offense stat in which 100 is league average.) Perdomo’s wRC+ has tracked almost perfectly with his line drive all year.

Unfortunately, while some hitters have more of a knack for liners than others, it is impossible to stop hitting fly balls and ground balls altogether. Last year, Los Angeles Dodgers first baseman Freddie Freeman led all qualified hitters with a line drive rate of 27.5 percent, which is only a couple of ticks higher than Perdomo’s line drive rate of 25.1 percent.

Realistically, while Perdomo is young and can get better, hitting more liners is not a viable strategy for meaningful improvement — or for maintaining his current performance, for that matter. To do that, he is going to have to start hitting the ball harder.

Why Geraldo Perdomo could struggle to maintain his success

It is not all that difficult to explain why Perdomo is unlikely to be an .850-plus OPS hitter the rest of the way. According to Baseball Savant, his expected batting average entering Thursday was just .206 and his expected slugging percentage was .281.

Those expected stats should be taken with a grain of salt, and they are not intended for predictive purposes. Nonetheless, baseball analysts generally agree that they provide a meaningful assessment of past performance. Suffice it to say that those stats make Perdomo look a lot more like the hitter he was last year than one of the best offensive shortstops in baseball.

While line drives are fantastic, that does not mean that hitting .784 on line drives — which is what Perdomo has done so far — is sustainable. Perdomo’s expected batting average on liners this year is .579.

Looking back through Perdomo’s line drive hits, it is not hard to pick out several that came in spite of poor contact quality. For example, here is a jam-shot liner down the left field line against Mike Soroka that went for a double.

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Perdomo has also had more than his fair share of luck on ground balls. He is hitting .340 on ground balls this year compared to an expected batting average of .196.

Here, a slow roller up the third base line turned into a double because the ball bounced off the bag:

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To be fair, expected stats are far from perfect, and it is reasonable to suggest that they could be undervaluing Perdomo’s ability to execute the so-called hit-’em-where-they-ain’t strategy. In particular, Perdomo’s knack for pulling liners down the line alone shows some ability to outperform expected stats. Expected stats, after all, do not take into account directionality.

On top of that, every hitter catches a break every now and then. Being able to pick out a few examples of lucky hits does not mean much.

Nonetheless, it is abundantly clear that Perdomo has had more than his fair share of favorable outcomes on batted balls this season. In fact, no player has a wider gap between his actual and expected stats this season than Perdomo.

Of course, that does not mean Perdomo cannot improve. He is still only 23, and his solid defense combined with his exceptional plate discipline are enough to make him a useful major leaguer.

Moreover, the fact that regression should be expected does not mean that Perdomo shouldn’t get credit for the way he has played so far. He has arguably been one of the five most valuable shortstops in baseball this year. No underlying stat can nullify that.

“His competitive nature,” Mather said, “That’s definitely something that you can’t quite put a number on. He goes up to the plate extremely focused, extremely determined, as much as anyone on our squad.

“Sometimes that can take over. Sometimes just that desire and that wanting to win the battle, him versus that pitcher, he’s relentless with it. That’s not going to show up outside of him just outperforming what people … think he’s gonna do.”

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Top photo: Charles LeClaire/USA TODAY Sports