Brent Rooker has had an up-and-down rookie campaign. Demoted to Triple-A following an injury-marred April, the 26-year-old outfielder logged a 141 wRC+ with 20 home runs in 62 games with the St. Paul Saints. He’s been less productive, yet no less promising, since returning to the Twins toward the tail end of July. In 153 plate appearances, the No. 35 pick in the 2017 draft has six long balls to go with a a 91 wRC+ and a .304 wOBA.

Those numbers aren’t a mystery to Rooker, nor are the swing analytics that help dictate what he’s doing in the batter’s box. Two partial seasons into what will hopefully be a long and productive big-league career, the former Mississippi State Bulldog is more than just an up-and-coming slugger: he’s a student of hitting.

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David Laurila: Do you view hitting as more of an art, or as more of a science?

Brent Rooker: “I think the best hitters are a combination of both. They’re very artistic in terms of what they feel and the way their bodies move. They know how to manipulate their bodies to allow them do what they need to do in order to accomplish what they want to accomplish in the box. But I also think the best guys know, statistically and analytically, what they do well and what they don’t do well. They use that to their advantage.

“Obviously, you have guys on both sides of the spectrum. Some guys are more feel guys, and others are more by the numbers and analytics. But again, I think the best guys — the truly best guys — are a combination of both.”

Laurila: That said, do you lean more toward one than the other? Read the rest of this entry »

On Wednesday, I took a swing at a question often asked of me: Which players have helped their Hall of Fame cases the most this year? In that piece, I highlighted 10 position players, some of whom have gained significant ground via JAWS, others who reached major milestones or simply returned to productivity after injury-plagued stretches. For this dispatch, I’ll first turn my attention to the pitchers, then backtrack to cover a handful of others — position players and pitchers — in a more lightning-round fashion.

For this exercise, I’m focused mainly on mid- or late-career players rather than early-career ones. All of the starters have a JAWS of at least 42.0; roughly speaking, that’s the equivalent of seven six-win seasons, a point at which I start to take mid-career pitchers seriously. JAWS and peak (WAR7) gains are the major drivers of this, but positional standards, traditional milestones, and ordinal rankings are considerations as well. For relievers, I’m using the WAR-and-WPA hybrid stat via which I’ve examined recent candidates such as Mariano Rivera, Trevor Hoffman, and Billy Wagner. All WAR (and WPA) figures here refer to the Baseball Reference version, unless otherwise indicated.

One other thing to note: since my reference point for “old” WAR and JAWS figures dates back to January 2021, some portion of these players’ gains may be due to updates to bWAR itself, particularly via changes to ’19 and ’20 park factors and tweaks to 2017–20 Defensive Runs Saved that were announced in March, but also due to a second update to 2020 park factors that just went live on Tuesday.

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There’s this episode of SpongeBob Squarepants that I love, in which Mr. Krabs’ snowballing desire for jellyfish jelly causes SpongeBob to catch more and more jellyfish until none remain. I bring this up because I like to imagine front offices as Mr. Krabs: Over the past few years, they’ve been shifting against more and more hitters, with seemingly no end in sight.

It turns out, however, we might have already reached the peak of infield shifting, at least in terms of volume. Comprehensive shift data dates back to 2016. Since then, here’s the rate of shifts against left- and right-handed batters each season:

This season, we’ve reached a point of stagnation. Teams haven’t budged from the mark they set against lefty hitters in 2020. Moreover, after a steady year-to-year increase, the rate of shifts against righty hitters has actually dropped. What I find more interesting — and ultimately want to dissect — is the latter trend. That teams aren’t looking for new lefties to shift against makes sense, since there’s presumably a limited pool. But righties demonstrate pull-side tendencies, too. If we assume teams are shifting mainly based on pull rates, we’d also expect the number of shifts against righties to keep climbing.

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In the days leading up to the trade deadline, Jarred Kelenic earned himself a mention in Jay Jaffe’s corner outfield replacement-level killers, a series that analyzes the players who are dragging down contending teams. The idea is to identify positions of need for potential trades to come, but Kelenic’s struggles in the majors weren’t going to force the team to make a deal. Instead, as Jay put it, “this should probably be a sink-or-swim situation unless he’s totally overwhelmed.”

Kelenic has already been in the spotlight because of the Mariners gaming his service time; his performance since his promotion has put him back in it. He got the call on May 13, but simply didn’t hit: In his first 23 games over a total of 92 plate appearances, he slashed .096/.185/.193. He collected just eight hits total and had come up empty in his last 44 plate appearances when the Mariners optioned him back to Triple-A in early June.

After a successful stint at Tacoma — a 137 wRC+ — Kelenic was brought back to Seattle. This time around, the results have been a bit better, but they’re still ugly overall, as he’s gone from a 10 wRC+ in that first stint to a .181/.263/.315 line and 65 wRC+ since his second promotion. Through Tuesday’s action, he’s up to a 45 wRC+ and -1.1 WAR in 64 games:

Even with the improved numbers since his return from Triple-A, Kelenic is still running the 11th-lowest wRC+ among qualified hitters in that time. He’s still not hitting well. But while there may not be one answer for why he is struggling, I believe that there’s a huge plate discipline problem that isn’t entirely captured in the walk and strikeout rates alone. Read the rest of this entry »

On Tuesday night, rookie sensation Wander Franco extended his streak of getting on-base at least once to an impressive 31 games. There’s still quite a ways to go before you make the shade of Ted Williams wonder if his 84-game (!) streak is in jeopardy, but it’s a mighty impressive feat for a 20-year-old.

That said, Franco is no ordinary rookie. As much a consensus No. 1 prospect as anyone I can ever remember, he didn’t exactly sneak up on anyone who was paying attention; his 80 Future Value grade — a first on our prospect lists — wasn’t something given out recklessly. At 18, an age at which minor league prospects are just getting started in the “real” professional leagues, he was already terrorizing the full-season Florida State League, hitting .339/.408/.464. That would be great for a first base prospect; for a young shortstop, it’s astounding.

Despite losing a key developmental season in 2020, Franco didn’t need much time to get going. Skipped right to Triple-A this year, he hit .315/.367/.586 for the Durham Bulls and was called up six weeks later. Outside of a home run in his very first game, the first week or two was an adjustment period; through 14 games, his line stood at .211/.274/.351 with 13 strikeouts in 57 at-bats against five walks. But since starting his on-base streak, he’s hit .314/.385/.504, also with 13 strikeouts but in 121 ABs.

Every streak has some element of good fortune, but in Franco’s running plate discipline numbers, you can almost see him adjusting to pitchers. And those numbers tend to be “stickier” than most other offensive numbers; short-term changes in results are more likely to be real compared to, say, batting average.

After his first two weeks in the majors, Franco’s contact rate increased despite him simultaneously swinging at more pitches. As pitchers in recent weeks have started throwing fewer strikes against him, that swing rate has responded accordingly, but his rate of contact has continued to rise. His performance during the streak isn’t exactly a galaxy away from his ZiPS minor league translation of .291/.335/.503 at Durham; combine that with the real improvements in plate discipline, and you can make a good argument that we’re seeing the bonafide Wander Franco in these waning days of summer.

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Which players have helped their Hall of Fame cases the most this year? The question comes up in almost every chat of mine, and sometimes in radio spots as well. You’d think I’d be used to this by now, but I rarely have more than an answer or two at the ready unless one of those players has recently been in the headlines for reaching a milestone. But with the end of the 2021 season in sight, and with the COVID-delayed Class of 2020 Hall of Fame Induction Day ceremony just a week away, it’s worth digging deeper for answers.

For this exercise, I’m focused mainly on mid- or late-career players rather than early-career ones. Yes, the five-win seasons of Vladimir Guerrero Jr., Juan Soto, and Fernando Tatis Jr. are solid steps towards attaining the ceilings we envision — and likewise for Shohei Ohtani given his singularly remarkable two-way season — but all of those players are at least half a decade away from the point when we can start to get real about their chances. JAWS and seven-year peak WAR gains are the major drivers of my selections in this piece and a companion one for pitchers, but positional standards, traditional milestones, and ordinal rankings are considerations as well. With one exception, all of the players below have surpassed 35.0 JAWS; roughly speaking, that’s the equivalent of seven five-win seasons, a point at which I start to take mid-career position players seriously. All WAR figures here refer to the Baseball Reference version, unless otherwise indicated.

One other thing to note: since my reference point for “old” WAR and JAWS figures dates back to January 2021, some portion of these players’ gains may be due to updates to bWAR itself, particularly via changes to 2019 and ’20 park factors and tweaks to 2017-20 Defensive Runs Saved that were announced in March, but also due to a second update to 2020 park factors that just went live on Tuesday. Read the rest of this entry »

Martín Pérez has a plus changeup, and he relies on it often. The 30-year-old native of Guanare, Venezuela has thrown his “cambio” 24.6% of the time since coming to the Red Sox prior to the 2020 season. A four-seam circle delivered at an average velocity of 84.9 mph, it’s the pitch the southpaw was once told would be his ticket to the big leagues.

Perez discussed the art of the changeup prior to a recent game at Fenway Park.

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Perez on his changeup: “I started throwing my changeup when I was 14 years old. Before that age, I just threw fastballs. I’d met couple of guys in Venezuela who played — Ramon Garcia, a righty with Houston, and Ernesto Mejia, who signed with Atlanta — and they told me not to throw breaking pitches, to just throw fastballs. As soon as I started my process to sign as a professional baseball player, I started to throw changeups, breaking balls, and fastballs.

“It’s important to have a changeup that will have the same arm speed as the fastball. You throw your fastball, and you throw your changeup, and they’re going to look the same. That’s why it’s so hard to hit. It’s hard for hitters to recognize that pitch, because they both have the same rotation. So, that was my focus.

“After I signed [with the Rangers] in 2007, the guy who was my boss at that time was [Director of Player Development] Scott Servais. In 2008, I played in [short-season] Spokane and it was a good year. I threw my breaking ball, my changeup, and my fastball. I had a big breaking ball. It was 12–6 and really good; I could throw it in any count. But then, in 2009, I went to Hickory, Low-A, and they told me, ‘Martín, you don’t have to throw more breaking balls. We want you to focus on your changeup, because that’s the pitch that’s going to take you to the big leagues.’ Read the rest of this entry »

As Kris Bryant helps the Giants fend off the Dodgers in the NL West division race, his replacement in Chicago seems like a lock to break his old team’s rookie home run record despite being older than Bryant is right now. Patrick Wisdom, who turned 30 on August 27, has swatted 25 home runs so far this season, coming out of nowhere to produce one of baseball’s most fascinating stat lines.

Prior to this season, Wisdom had just 27 games of big league experience, including two with the Cubs in 2020, who re-signed him to a minor league deal in January. Though he posted “ridiculous” numbers at the team’s alternate training site last season, he seemed more likely to provide bench depth for the big league club than be a regular, only to end up playing 83 games split between first base, third base and left field, take 279 plate appearances, and post a .256/.320/.579 slash line.

There remain questions of sustainability. Wisdom isn’t a true-talent 136 wRC+ player, but he’s certainly more of a viable big league bat than initially thought. ZiPS projected him for an 82 wRC+ before the season, which was much more bullish than Steamer’s 70 wRC+ prediction, but both are still a far cry from the actual numbers so far. As a result, both systems have seen significant improvement in the underlying talent given the sizable sample of good performance: His rest-of-season ZiPS projection has him up to a 104 wRC+, and Steamer has him at 93. Read the rest of this entry »

Corbin Burnes is laying waste to the National League, putting up numbers that can best be described as comical. A 34.6% strikeout rate? That’s closer territory. A 4.8% walk rate? That’s lower than Kyle Hendricks’ career mark. His 2.27 ERA might undersell how good he’s been; both his xERA (a Statcast ERA estimator) and FIP are in the ones (1.96 and 1.58, respectively).

You know about the cutter he leads with, which he described to David Laurila earlier this year. You know about the slider and sinker, the two pitches that complement his cutter. That trio took the league by storm last year, and he’s doubled down on cutters this year; he now throws the pitch roughly half the time.

Like an annoying hipster, though, I’ve moved on to the next cool Burnes thing that no one is talking about yet. The cutter? It’s fine, I guess (it’s the best cutter in baseball, but I’m doing a bit here, so bear with me). I’m here to talk to you about the curveball, a pitch that he threw less than 10% of the time before making it a staple this season.

If Burnes has one standout skill, it’s his ability to impart spin. Even when he was bad, he threw the highest-spinning four-seamer in the game, and his slider has always jumped out of his hand. It’s hardly a surprise that his curveball is cut from the same cloth. Spin data is fraught this year, what with the foreign substance crackdown and all, but since June 21, he’s thrown his curveball with a whopping 2,840 rpm, the 16th-best mark in the game (21st-best if you consider spin-to-velocity ratio instead).

What does that mean in English? It means that he has the raw stuff to generate eye-popping movement. He also throws the pitch in the low 80s, which means batters don’t have a ton of time to react. Put those two things together, and you can make MVP candidate Buster Posey look like a toddler learning how to walk:

The pitch is an absolute delight, and it’s also phenomenally effective. Batters have come up empty on half of their swings against it, the third-highest mark in the league (and 45% since June 21, so don’t go sticky-stuff-asterisking up this great pitch). As an added bonus, he’s seventh in baseball when it comes to batters not swinging at pitches in the zone. He throws it for a strike 49.3% of the time, which ranks seventh in the majors, and batters take it, doing his work for him. Can’t hit it when they swing at it, often take it when they should swing at it: what’s an opposing hitter to do but complain?
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One of the biggest reasons the Mariners have stuck around the fringes of the AL wild card race despite a -60 run differential has been the collective performance of their bullpen. Kendall Graveman had established himself as a bonafide relief ace before being traded to the Astros in late-July, and Drew Steckenrider has revived his career after falling apart in Miami two years ago. But equally unexpected, and perhaps the biggest reason Seattle felt comfortable dealing Graveman at all, has been the fantastic season put together by its other breakout relief ace: Paul Sewald.

Drafted as a reliever by the Mets in the 10th round of the 2012 draft, Sewald came with two years of college experience under his belt at the University of San Diego and quickly moved through the farm system. He reached the majors in 2017 and made 125 appearances out of the bullpen through 2020, but outside of a 23.5% strikeout rate that was just a hair above league average, he was mostly forgettable as a Met; across 147.1 innings in New York, he posted a 5.50 ERA. He was non-tendered this past offseason and signed a minor-league contract with the Mariners in January.

Even though Sewald wasn’t able to make the major league roster out of spring training, he has thrived in Seattle. He was called up on May 13, the same day Jarred Kelenic and Logan Gilbert made their debuts, and while his return to the majors was much less heralded than those two top prospects, he’s arguably been more important to the Mariners this season than either. He’s upped his strikeout rate to 40.3% in 2021, the fifth highest rate among all qualified relievers, and all those strikeouts have helped him drop his FIP to just 1.95. In just 45.1 innings, he’s more than doubled his total career WAR.

Michael Ajeto of Lookout Landing was one of the first to write about Sewald’s breakout, but the reasons for his improvement are tough to spot on the surface. He’s simplified his pitch mix a bit, cutting out his rarely thrown changeup and increasing the usage of his slider to make him a two-pitch pitcher:

Both the fastball and slider are returning better-than-ever results, with the latter generating a 38.6% whiff rate and a .270 wOBA against. But as good as his breaking ball has been, the four-seam fastball has been even better. Its whiff rate is up to 35.3%, the 12th-highest mark among all four-seam fastballs thrown at least 100 times this year, and it boasts the 12th-highest CSW% (35.7) in that group.

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