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The 2022 MLB regular season is less than two weeks old and, to be completely honest with you, this is the worst time of year to analyze baseball. The sample sizes are so small and it is damn near impossible to differentiate what's meaningful from what's nothing more than baseball being weird. But, we soldier on.

With that in mind, our weekly series breaking down various trends across the league continues Wednesday with a look one rookie's tough luck strike zone, another's unique pitch, and the league-wide home run rate. Last week we examined Steven Kwan's historic start, Julio Urías' missing velocity, and the decline in stolen bases.

Rodríguez's rookie strike zone

Julio Rodriguez
SEA • CF • 44
BA0.143
R4
HR0
RBI1
SB4
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By all accounts Mariners outfielder Julio Rodríguez is one of the best prospects and most talented young players in baseball. Our R.J. Anderson ranked Rodríguez the game's No. 3 prospect this spring, saying he has "well-above-average power and a better feel for contact than most with this profile." Nearly all other publications ranked Rodríguez as a top three prospect as well.

That said, Rodríguez's introduction to the big leagues has been bumpy. He is 5 for 35 (.143) with 17 strikeouts through 10 games. That's OK. Countless young players needed some time to find their footing at the MLB level (when's the last time you looked at Mike Trout's 2011 stats?), though that doesn't make it any more fun to sit through. Growing pains are a bummer.

This is not to absolve the 21-year-old Rodríguez of blame for his poor start -- he's been bad and it's OK to say it, and it doesn't mean he'll be bad forever -- but I do want to note he's dealt with a less than perfect strike zone. Let's call it the rookie strike zone, the old-school idea that a young player won't get borderline calls in his favor until he proves himself in the show.

Already six times this year Rodríguez has struck out looking on a pitch outside the strike zone. Yoshi Tsutsugo has done it five times, and Ji-Man Choi and Lourdes Gurriel Jr. have done it three times. No other player has done it more than twice. Look at some of these called strike threes against Rodríguez. A few are egregious:

Going into Tuesday's games, only five hitters had more called strikes on pitches outside the zone go against him than Rodríguez, regardless of count. Hitting in the this league when you're less than two weeks into your career is hard enough. Hitting when so many calls go against you is even tougher. These calls swing count leverage and generally make life hard on the hitter. 

As tempting as it may be, Rodríguez has not blown up at an umpire yet. He's done nothing more than have a few quick words for the ump after a called strike on a pitch out of the zone. There's a way to be respectful and tell the umpire you disagree with his call without making a scene or get ejected. Rodríguez has done well to walk that line thus far.

I know "it'll even out over time" is not a satisfying answer, but that's really all Rodríguez can do at this point. Wait for the calls to even out. Expanding the zone and trying to hit those pitches will only lead to bigger problems. For a rookie, Rodríguez is doing a decent job of swinging at the right pitches (36.8 percent chase rate). It's just that a few scattered calls have gone against him.

Rodríguez has been rung up on a few pitches outside the zone in the early going and who knows, maybe he would have eventually struck out in those at-bats anyway. The kid has been the victim of a pitcher-friendly strike zone thus far though. It's happened. Soon enough the tide will turn, and I suspect he'll get settled in and begin producing at a clip expected of a top prospect.

Duran's splinker

Jhoan Duran
MIN • RP • 59
ERA6.00
WHIP1.33
IP6
BB2
K11
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The new pitching craze these days is the "sweeper," or a hard slider with a ton of horizontal movement. Andrew Heaney added one with the Dodgers and is dominating. The Yankees and Rays are among the clubs teaching their pitchers sweepers as well. Thanks to advanced pitch data and high-speed cameras, pitches are literally designed in a lab and taught to the staff nowadays.

Some pitches can not be taught, however. Pedro Martinez's ultra-flexible fingers made replicating his changeup impossible. Twins rookie righty Jhoan Duran also appears to have a pitch that is unique to him. It's been dubbed the "splinker," and is essentially a split-finger sinker. It is a vicious pitch that combines upper-90s velocity with a splitter's nosedive. Look at this:

Duran has had the splinker for years. Baseball America first wrote about it in 2019, when Duran was in High Class-A. It's just that Duran is now in the big leagues and we're seeing it in action. It's no longer hidden away in the minors. As you can see in the GIF, the splinker is nothing more than a traditional splitter grip, yet to moves like that at that velocity. Watch it at full speed. This is nuts:

"It's not really a one-pitch-wonder kind of deal, but it's like, there are pitches that only one person has in the game," Twins manager Rocco Baldelli told MLB.com's Do-Hyoung Park about the splinker. "I think this pitch is a pretty unique pitch. I don't know how you prepare or game-plan or think about a pitch like that as a hitter. I've never seen anything like it in my life. I can honestly say that."  

Duran, 24, has allowed four runs in six big-league innings thus far, though he's struck out 11. He's thrown 31 splinkers, hitters have swung at 20, and they've missed 10 times. Duran did leave one splinker up enough for Christian Vázquez to hit a homer, but that 50 percent whiff rate is off the charts. The league average for splitters is 38 percent (the highest among all pitch types).

The Twins are using Duran in relief now and that might be his long-term home. He has a bit of an injury history and his slider is not a reliable third pitch. It could be Duran is Minnesota's closer of the future as a guy with an upper-90s heater and the splinker, a pitch that is unique to him. In this era of pitch design, there is no replicating the splinker. It is Duran's and Duran's alone.

"You get the, 'Holy ... how does he throw that?'" Twins catcher Ryan Jeffers told Park about hitters seeing the splinker for the first time. "All sorts of reactions like that. You get a lot of hitters looking pretty silly."  

The cratering home run rate

Two weeks ago in this very space I noted the spring training home run rate was astronomical. It was higher than the 2019 regular season home run rate, when MLB smashed its previous single-season homer record. Generally speaking, the regular season home run rate tends to be higher than the spring training home run rate, so we were in for a ton of homers in April, right? Nope. Wrong.

Thus far the regular season home run rate is the lowest it's been in years, and substantially lower than the spring training home run rate. Look at the home runs per balls in play rate the last few years (ignoring the unusual 2020 season):


Spring training HR/BIPApril HR/BIPRegular season HR/BIP

2017

4.0%

4.5%

4.8%

2018

4.5%

4.2%

4.4%

2019

4.7%

5.2%

5.4%

2021

5.0%

4.7%

4.9%

2022

5.5%

3.8%

???

Your eyes did not deceive you. A lot -- A LOT -- of home runs were hit in spring training. And no, your eyes do not deceive you now. The home run rate is way down since Opening Day. Over the weekend Jeremy Frank noted only 15 homers were hit in the 14 games Sunday. It's the fewest homers in a day with at least 14 games since Sept. 2014, and the fewest in a day in April since 1993.

There are three possible explanations. One, it's just a small sample blip. That's possible, though we're already over 8,000 balls in play for the season, so the league-wide home run rate should be pretty stable. It'll climb as the weather warms up in the summer months, but at this point, it is what it is for April. The league-wide rate won't fluctuate much on a daily basis two weeks in.

Two, it's the humidor. MLB is using a humidor in all 30 ballparks for the first time this season (it was in 10 parks last season) and the humidor brings the baseball to average humidity. It dries the ball in humid climates (like Florida, even in a dome) and "wets" the ball in dry climates (like Arizona). The drier the baseball, the more it flies, and the more home runs we'll see.

For the humidor to account for the large drop in home run rate, it would mean MLB has played a disproportionate number of games in dry climates, so the humidor "wet" the ball and deadened it. We know that's not the case. We know where games have been played. It's possible the humidor is playing a role in the home run rate decline. It's unlikely it is the reason for it, however.

And three, it's the baseball itself. We were supposed to get a deadened baseball last year. Instead, we got a deadened baseball and also the 2019 rocket ball, and we don't know which ball was used in which games. MLB said the "2022 season will be played with only balls manufactured after the production change," and I guess that means the deadened ball? It certainly seems that way.

The baseball is the simplest explanation. We have no idea how the ball will play season to season, though at least last year MLB told us to expect a deadened baseball. We didn't get it fully, but maybe we are now? The humidor could be contributing to some degree, and maybe the short spring training and deep pitching staffs too. Hitters still seem to be behind the pitchers.

Whatever the reason, the home run rate since Opening Day is lower than it's been at any point since at least 2016. Run scoring is down and the league-wide batting line sits at .231/.310/.373. And that's with the universal DH, remember. Offense will rise as we get into the summer months. Right now though, this is a pitcher-friendly league.