Weighing Javier Baez’s Terrible MLB Debut

To say Javier Baez had a rocky start to his big league career would be an understatement. After tearing up the minor leagues to the tune of .274/.331/.541, the 21-year-old rookie hit a putrid .169/.227/.324 in 52 games with the Chicago Cubs last year. His on base percentage was the lowest of any hitter who recorded at least 200 plate appearances last year.

Baez’s atrocious performance had a lot to do with his alarming strikeout numbers. Swing and miss has always been part of Baez’s game, but his contact issues rose to unprecedented levels once he began facing big league pitching. In Double-A and Triple-A, Baez posted strike out rates of 29% and 30% respectively, but whiffed 42% of the time in the majors

Baez’s contact problems were unprecedentedly chronic. Just 59% of his swings resulted in contact, which is the lowest mark we’ve seen in the PITCHf/x era. However, Baez’s Contact% only tells part of the story. It reveals that many of his swings didn’t lead to contact, but doesn’t tell us why.

A deeper dive reveals that — despite his violent swing — Baez’s raw contact ability isn’t as terrible as you might think. He just swung at a lot of pitches that he probably shouldn’t have, which resulted in a lot of swings and misses. His Z-Contact% — the percentage of pitches he connected on within the strike zone — was actually higher than 17 hitters with at least 200 plate appearances last year. Baez’s swing-and-miss was bad, but not fantastically bad.

His plate discipline, however, was undeniable terrible. He swung at more pitches outside of the strike zone (39%), and fewer within it (58%) than the average hitter. His Correct% — the ratio of pitches where he either swung at a strike or didn’t swing at a ball — was the second worst among players with at least 200 plate appearances last season. The only hitter with a lower percentage was Reed Johnson, who apparently got 200 plate appearances last season.

Baez’s poor plate discipline is nothing new. His O-Swing% and Z-Swing% were closer together than you’d like them to be in the minors as well. However, his problems accentuated once he reached the big leagues.

Here’s a look at how these two metrics correlate from Triple-A to the majors. This considers all hitters since 2011 who recorded at least 100 plate appearances in both Triple-A and the majors. Baez’s big league O-Swing% and Z-Swing% were both worse than you’d expect based on his minor league numbers.

Baez wasn’t quite as terrible at deciding when to swing before his call up. It seems like major league pitchers did a better job of attacking Baez’s weaknesses than their minor league counterparts. It didn’t take long for pitchers to identify his weak spots: Above the strike zone and down and away. Lots of pitches in these locations…


But not much contact…


Without a doubt, Baez’s rough debut should cause us to re-evaluate our expectations for his upside. However, it’s hard to know just how much we should do so. As bad as Baez was as a Cub, his performance covered only 229 plate appearances. Held against 1,433 plate appearances of 136 wRC+ from the minors, it’s obvious that Baez is a better player than his big league stat line would have you believe. Plus, at least in theory, he could significantly improve by simply laying off of pitches outside of the strike zone

Based on his 434 plate appearances from Triple-A last year, Baez earns a KATOH projection of 7.6 WAR through age-28. This forecast was the 12th highest among hitters with at least 400 plate appearances last year. That’s an encouraging projection, but it’s also a projection that ignores the most recent data on Baez, namely, the 52 games where he fell flat on his face as a big leaguer.

KATOH was only designed to analyze minor league stats, so it has nothing to say about Baez’s major league performance. But what if his two months in the Windy City had instead taken place in Triple-A Iowa? Would KATOH still think highly of Baez’s future outlook?

I decided to run the numbers to find out. Below, you’ll see three iterations of KATOH projections for Baez: One based strictly on his numbers from Triple-A, one based only on his numbers from the majors and one a weighted average of the two.

Level MLB >4 WAR >6 WAR >8 WAR >10 WAR >12 WAR >16 WAR WAR thru 28
AAA 97% 37% 35% 28% 25% 24% 19% 7.6
MLB 44% 0% 0% 0% 0% 0% 0% 0.9
Weighted Average 79% 24% 23% 18% 16% 16% 12% 5.3

Here’s a visual, for those of you who prefer your data in the form of pictures.


The weighted average projection weighs the two pieces of Baez’s season strictly in terms plate appearances, without accounting for the fact that his 200+ plate appearances in the majors happened more recently. You could certainly argue the more recent chunk should receive a larger share of the weight. However, this analysis also treats his big league struggles as if they happened in Triple-A, which sells Baez a bit short. Overall, it’s probably not too much of a stretch to say these two effects more or less even out.

As we already knew, Baez’s forecast looks excellent when we only consider his Triple-A numbers. Unsurprisingly, the MLB iteration is a lot less encouraging. However, when taken together and weighted by sample size, the end result isn’t all that bad. His 5.3 WAR would have put him 29th among minor leaguers with at least 400 plate appearances, a few spots ahead of both Joey Gallo and Steven Souza.

Baez’s big league debut was a huge disappointment. There’s no way around it.  Even if he were to hack 10% off of his strikeout rate from last season, he would still have one of the highest strikeout rates in baseball. There’s plenty of reason to worry about Baez’s offensive game going forward, but he does still have plenty of redeeming qualities.

For one, he still has age on his side. He will be just 22 years old in 2015, and looks like a good bet to spend most if not all of the year in the big leagues. Of the 136 hitters who racked up at least 2 WAR last year, more than half (79) spent their age-22 seasons entirely in the minors. Regardless of what Baez does this year, he’ll still be a ways ahead of many prospects his age. There’s still plenty of time for him to make much needed adjustments.

Additionally, he can  provide value on defense, which makes his poor OBPs much easier to swallow. By no means is Baez a great defender, but he’s played shortstop as recently as last season, so there’s no reason to think he can’t be at least an average defender at second base. The offensive bar is much lower for middle infielders, which means Baez doesn’t necessarily need to be a great hitter to be a useful player.

Baez was scary bad last year, but it’s still far too soon to slap him with the “bust” tag. He tore it up in the minors, and has been drawing rave reviews from scouts for years. A poor two months as one of the youngest players in the majors isn’t nearly enough to wipe all of that away.

We hoped you liked reading Weighing Javier Baez’s Terrible MLB Debut by Chris Mitchell!

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Chris works in economic development by day, but spends most of his nights thinking about baseball. He writes for Pinstripe Pundits, FanGraphs and The Hardball Times. He's also on the twitter machine: @_chris_mitchell None of the views expressed in his articles reflect those of his daytime employer.

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Timely, as Baez just got optioned to AAA.


Good news for Alcantara


Alcantara will be sent down and Baez will replace him. I just got back from the future…