Mike Yastrzemski, Patient Thumper

There weren’t a lot of bright spots on the 2019 San Francisco Giants. Pablo Sandoval was fun here and there, particularly when he pitched. Alex Dickerson hit a few dingers. Donovan Solano isn’t cooked just yet. For the most part, though, those were marginal. The real splash, the only real splash, was Mike Yastrzemski, who went from feel-good legacy to bona fide major league outfielder in the course of one slugging season.

2019 was already surprising enough for the career minor leaguer. After showing flashes of patience, power, and a feel to hit in previous seasons, he put them all together in Triple-A Sacramento, and there was no one blocking him from the majors. Four hundred plate appearances and a .272/.334/.518 batting line later, he was the best outfielder on the team, and the Giants were constructing their 2020 roster with one spot on the depth chart written in pen.

If the start of 2020 is any indication, however, last year wasn’t Yastrzemski’s ceiling. His ceiling is this year’s white-hot start: .310/.473/.643 with three homers, good for a 204 wRC+. Oh yeah — he’s playing freaking center field every day, too. Twelve games does not a season make, but if you could make his whole season out of the last two weeks, he’d basically be Mike Trout — an up-the-middle defender with a 200-ish wRC+.

Is he a good fielder? It’s unclear. He looked good both by the eye test and by the advanced statistics troika of DRS, UZR, and OAA last year in the corners, and looks at least reasonable in center so far this season. He’s not a long-term premium defender — he’s nearly 30, for one thing, and has only average straight-line speed — but tuck him in a corner, and he’ll be inoffensive at worst and an asset at best.

But the exciting part about Yastrzemski isn’t the fielding, at least not mostly. It’s the offensive value, the leading-baseball-in-WAR offensive explosion that makes Giants fans mostly shrug their shoulders but also rub their hands together greedily when they think no one’s looking. Sure, it’s early. Sure, it’s not our year. But it could be real, right? The team could have found a new superstar, right?

Probably not, sadly enough for this hypothetical Giants fan. But take heart! Yastrzemski’s isn’t that common early-season breakout, the BABIP false idol, at least not entirely. It’s kind of that, of course: he has a .385 BABIP through 12 games, and that’s not sustainable, even if his contact quality suggests he’s above average in that department. Per Statcast, his expected BABIP last year was .329, and ZiPS and Steamer both project tallies above the .300 naive estimate we all use in our heads (.311 and .307, respectively).

That’s not .385, which means it’s a good idea to lower expectations for his average on contact. Not even the pie-in-the-sky-est fan would expect a guy striking out a quarter of the time to keep batting .300. What about that sweet, sweet power, though? Surely that isn’t affected by the vagaries of whether singles fall in. Dingers and doubles aren’t a matter of the ball finding a hole; they’re the batter making a hole.

Sadly, I’m not totally sold on the newfound power either. I don’t think it’s a complete mirage or anything, but a .333 ISO is the domain of Mike Trout and Christian Yelich. You need some serious thump to get that many extra bases sustainably, and that means stacks and towers of barrels, barrels you can’t even see over, if you want any shot at such power.

Yaz (look, we’re pretty far into this article and we’re all friends here, I’m going to stop going full last names if that’s alright with you) gets into some power, no doubt. Last year, he barreled up 11.2% of his batted balls, an 82nd-percentile mark in the major leagues (minimum 100 batted balls) and far ahead of the overall average of 7.4%. He’s off to a strong start there as well, with four barrels already in 2020 (13.8%).

In fact, barrel rate alone can tell you a lot about power production. By itself, it has a 45% r-squared to slugging percentage. In other words, 45% of the variation in slugging percentage is explained by variation in barrel rate. That’s massive — slugging percentage cares about things like singles and strikeouts, while barrel rate just looks at how often the ball goes a long way in the air. If he had the slugging percentage “predicted” by his barrel rate this year, Yastrzemski (I switched back! I don’t know why!) would still be slugging .517, not shabby at all.

Did I do all this work only to tell you that Mike Yastrzemski is actually pretty great, that you should mostly believe the hype? Kind of! xwOBA, or expected weighted on-base average if you’re a full words type, is Statcast’s measure of expected offensive production based on how hard and at what angle each batted ball is hit. By that metric, Yastrzemski is elite this year, producing at a rate that would have been in the top 10 across all of baseball last year.

Here’s the thing, though: he’s not doing it just with those barrels. An 82nd-percentile barrel rate is nice, but not top-10-in-baseball nice. He’s not spraying line drives everywhere to make up for it. No, the real juice in Yastrzemski’s offensive game this year is a raftload of walks — so many walks, 13 already in only 12 games.

If you want to know whether this hot start can continue, focus on the walks and strikeouts. You don’t have to be a very good hitter on contact to succeed when you’re walking 23.6% of the time, even if you’re also striking out 23.6% of the time. More specifically, you could produce a .292 wOBA on contact and have the whole ball of yarn work out to average overall production. League-wide wOBA on contact (wOBACON if you’re hungry) was .378 last year. Yastrzemski’s wOBACON was .449. The walks are absurd, is my point.

How did he start walking so much? The numbers tell a clear story. If you want to walk a lot, my advice is simple: stop swinging at pitches outside the strike zone. Here’s a list of the batters swinging outside the zone least frequently in 2020:

Lowest Chase Rates, 2020
Player O-Swing% BB%
Trent Grisham 14.0% 15.1%
Max Muncy 14.9% 15.3%
Mark Canha 15.0% 23.8%
Mookie Betts 16.8% 8.2%
Yoshitomo Tsutsugo 17.0% 10.5%
Cavan Biggio 17.1% 8.3%
Brian Goodwin 17.2% 13.2%
Carlos Santana 17.7% 20.8%
Mike Yastrzemski 18.0% 23.6%
Yandy Díaz 18.1% 20.9%

Hey, neat. Another bad thing you can do, if you’re intent on walking as much as possible, is swing at pitches in the strike zone, provided there are less than two strikes in the count. We’re focusing on walking to improve your offensive value here, though, not walking for its own sake, so let’s modify it slightly. Here’s a list of the players who have swung least frequently at pitches on the fringes of the zone (but, to be clear, still inside the zone) with fewer than two strikes:

Avoiding the Edges
Player Swing Rate
Ildemaro Vargas 5.3%
Nico Hoerner 11.8%
Mike Trout 11.8%
Victor Robles 17.6%
Mike Yastrzemski 21.1%
Yandy Díaz 21.7%
Max Muncy 24.4%
Manuel Margot 25.9%
Jacob Stallings 26.3%
Ramón Laureano 27.9%

It’s still a minuscule sample. In fact, minuscule might oversell it — Trout, for example, has swung at two of the 17 such pitches he’s seen. Still, Trout isn’t on this leaderboard by accident, and Alex Bregman is just off the list at 12th. Good patient hitters wait these pitches out, because there will be better pitches to hit, or better pitches to take for a walk. The power of not having two strikes is that you aren’t compelled to swing at everything in the zone if you don’t think you can do damage on a given pitch.

If there’s something worrisome about this, it’s that Yastrzemski has never shown this skill before. Last year, he swung at 50.3% of such pitches. Could it just be random variation, a fluky spike of variance at the start of the season?

I think not. So far this year, he’s seen 38 such pitches. Take a look at last season in a different way, a rolling 38-pitch average swing rate. Not once did he show nearly so much restraint as he has this year:

This approach isn’t without its flaws. It should, in theory, lead to more takes in the heart of the zone; thinking “only swing if it’s good” puts you in a take mindset. So far, however, it hasn’t. In 2019, Yastrzemski swung at 65.2% of pitches over the heart of the plate (the strike zone minus the edges) with less than two strikes. In 2020, it’s fallen — all the way to 63.4%.

It’s not hurting him with two strikes, either. Last year, he swung at 83.9% of those edge pitches with two strikes, which is good practice: you have to engage with those pitches when a strike ends your turn at the plate. This year, he’s swinging at 84.6% of them, though to be fair that’s 11 out of 13. Swing less often when you shouldn’t, swing as often when you should: that’s a neat trick.

That doesn’t mean this new approach should yield a 23.6% walk rate, to be clear. There’s still plenty of luck involved. It does mean, however, that he’s not up there walking by accident. He has a new plan, and it’s working. Strikeouts are a side effect of deep counts, and he’ll continue to run high rates there unless he miraculously improves his contact rate, but this isn’t just a run of facing a few pitchers with control problems. He’s doing something measurably different, something unlike anything he did last year, and it’s paying off.

Pitchers will adapt; they’ll have to. They’ll try to take advantage of his new patience or hone in on a pitch he has the most trouble taking. For now, though, bump up your mental estimates of his future production if you still thought he was last year’s model. He’s a different hitter now, a better one. And hey, as a bonus for sitting through this long article, with its convoluted bucketing of pitches and the long protagonist surname, here’s Yaz giving a kayaker a souvenir:

Ben is a writer at FanGraphs. He can be found on Twitter @_Ben_Clemens.

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3 years ago

Maybe the new approach came from a talk with grandpa, one of the more patient hitters of his day. Averaged 90 walks per 162-games for his career.

3 years ago
Reply to  Dewey24

They are reported (by Him) to talk a lot.