The Incredible Platooning Jorge Polanco

Jorge Polanco has always been a good hitter. He has a career 111 wRC+, and since he started getting regular playing time in 2016, he’s finished with a wRC+ below 100 only three times, one of which was the pandemic-shortened 2020 season. But he’s played 20 games so far this season, and he’s never had a 20-game stretch quite like this. He’s batting .377 with a 233 wRC+. How is Polanco – while injured – running the fifth-best xwOBA in baseball and second-best overall batting line?

As I mentioned, Polanco isn’t 100%. He underwent surgery in October to repair his left patellar tendon, and soreness in that knee has already cost him a couple of games this season. Polanco has also been dealing with a minor oblique strain, which has kept him from hitting right-handed since March 31. Polanco has a career 118 wRC+ as a lefty and a 95 wRC+ as a righty. That’s a legitimate platoon split, but it’s not big enough that we should have expected him to turn into Babe Ruth once he quit batting right-handed. Moreover, you have to imagine that the injury is slowing him down at least slightly, even from the left side. Maybe I’m wrong here, but it’s just hard to believe that any baseball swing could be completely unaffected by an oblique injury.

Just to recap, Polanco has a minor injury. He’s only batting left-handed and (with the exception of one plate appearance that ended with a strikeout) only facing righties. He’s also DHing and getting days off to protect the oblique. Oh, and he’s been the best hitter in baseball (non-Aaron Judge division). So let’s figure out what’s going on. We’ll start with the basics. Here are Polanco’s numbers from each of the five most recent seasons.

First of all, Polanco is putting the ball in play an extraordinarily high percentage of the time. He’s running a walk rate that’s less than half of his career mark. His strikeout rate is less than half of what he posted in either of the past two seasons. Last year, he put the ball in play 60% of the time. This year he’s at 84%. He’s swinging a lot and making a lot of contact. He’s hitting for a high BABIP, and I’m sure he’s benefitting from a bit of batted ball luck, but most of this production is about the .362 isolated slugging percentage. That’s not to say that we’re not dealing with small sample size luck here — I definitely think we are, and we’ll get to that later — but for now, the takeaway is that Polanco has become much more aggressive at the plate and started slugging more. That’s what’s going on here. Polanco is swinging a lot, and he’s really, really slugging.

He’s also swinging the bat harder. To some degree that makes sense. During the very end of the 2023 season, Polanco had a 71.2-mph average bat speed from the left side. That dropped to 70.2 during 2024, when he was limited by a series of knee and hamstring injuries that culminated in the surgery. He was really banged up. This season, he’s up to 71.6 mph. However, that’s still below the league average. Polanco may be back to normal, or even slightly better than he was in 2023 (a year when he also dealt with some knee and hamstring issues), but it’s not like he’s suddenly turned into Giancarlo Stanton. His bat speed is fine, but on its own, it’s not the reason he’s unstoppable.

So Polanco is swinging harder, and he’s very definitely hitting the ball harder.

His 56.9% hard-hit rate from the left side is way better than anything he’s done over the course of an entire season, or even over a single month (with the exception of June 2024, when he played in just five games). So is he swinging at better pitches? Is he hammering fastballs? Not really. Instead, he’s hammering everything like it’s a fastball.

This is where things get weird. Despite this drastic increase in hard contact, Polanco’s 90th-percentile exit velocity has basically stayed the same for the last several years. So although he’s hitting the ball hard much more often and his average EV is way up, it’s not like he’s found a new level of power. And as I mentioned, it’s not like his plate discipline is much better; he’s hitting the ball harder, but not because he’s choosing better pitches to hit. He’s just squaring everything up, especially offspeed pitches. As a lefty, Polanco has a .582 wOBA and .586 xwOBA against offspeed stuff this season. His previous highs were both under .335. Polanco is still whiffing at roughly 28% of the offspeed and breaking pitches he sees, just like he always has. But in the 27 times he has made contact, he’s crushed the ball.

If you’ve been watching him this season, you’ll know that Polanco also looks different at the plate. He came up in 2015, and in 2019, he switched to a very open stance. That stance had stayed more or less the same over the years. Until this season.

He has held onto that slight tension, in which he leans back with his shoulders rolled further away from the pitcher than his hips. However, he no longer has an open stance. In fact, by the time the pitcher releases the ball, his stance is slightly closed. He’s also more upright in the box, and his hands are starting out much closer to his ear.

The mechanics are different too, quieter. Polanco’s leg kick is much more subtle, and he’s drastically reduced his hand load. The two pictures below are from the moment the pitcher releases the ball. Both pitches are four-seamers over the middle that he crushed. In the photo on the left, which shows a plate appearance from 2024, you can’t see Polanco’s hands at all, but you can see his elbow sticking way back behind him. His bat is wrapped, so that the barrel is facing the pitcher slightly. The photo on the right is from this season, and there are Polanco’s hands, pretty much right where they started out. At this point, his leg isn’t raised at all.

Players make these kinds of changes when their goal is to prioritize timing and quickness. This is a simpler swing, and usually the goal of simplifying your swing is to make sure you’re on time. It helps you prioritize quickness. It seems to be working. According to Baseball Savant’s new batting stance metrics, Polanco’s average point of contact is farther out in front of home plate.

In all, it makes for a shorter stroke, and the change at the end is similar to the change at the beginning. You can see it in the full swings above. When Polanco finishes his swing this season, his follow through tends not to whip him around quite as far. He looks more linear, less rotational than he did last season. He’s relying on shorter, more explosive movements rather than longer ones. That helps explain why, even though he’s seen such a drastic improvement in bat speed, his average swing length has only increased by just over an inch.

I should stop for a moment and be clear that I’m just talking about Polanco’s left-handed swing here. His right-handed stance has never been quite so open, and he hasn’t closed it this year. However, he has seemed to simplify his load in the same way from the right side.

Time for another quick recap. Polanco is healthier, sort of. He’s drastically overhauled his swing to prioritize quickness, and he’s gained a lot of bat speed without making his swing much longer. He’s making contact farther out in front of the plate, hitting the ball harder, and hitting a lot more line drives. It’s not just the line drives either. His launch angles in general have become much more concentrated.

That’s always a good thing. Polanco is rarely hitting lazy fly balls or routine groundouts. However, I need to end by throwing some cold water on what you’ve just read. It’s always exciting when you see a swing change that pairs up so neatly with the player’s results, but I need to point out a few things.

The first is obvious. Regression will come for Polanco at some point. I don’t think anybody is expecting him to keep hanging out in Aaron Judge territory indefinitely. He’ll cool off at some point, and his massive 29% HR/FB rate will come down to Earth. Because he’s never walking and never striking out, his game is extremely BABIP dependent, which leads to streakiness, just like we’ve been seeing. Presumably, he’s not just going to hit scalding line drives forever, because people tend not to do that.

The second is that the graph I showed you at the beginning of this chart was slightly misleading. It was a 20-day rolling average of his wRC+, and it made it very clear that Polanco had never had a 20-game run like the one he’s on right now. He’s never even come all that close. But I need to remind you that Polanco is only batting left-handed. He’s sitting against lefty starters and getting pulled against lefty relievers. He’s made only 75 plate appearances this season, and he’s reached five plate appearances in a game only five times. So while he’s appeared in 20 games, he’s only accrued roughly 15 games’ worth of plate appearances. Basically, I was asking the wrong question. The better one is this: Has Polanco ever had a 15-game stretch like the one he’s been on this season? Yes, many times.

Keep in mind that Polanco is usually a switch-hitter, so each of those other peaks came while he was also watering down his performance with worse hitting from the right side. For that reason, I also pulled Polanco’s performance from just the left side of the plate and made my own 15-day rolling graph of his wOBA.

Once you throw out right-handed plate appearances, you see that Polanco has had better stretches in recent years. We’re absolutely seeing something great, but we’re not necessarily seeing something new. His bat speed is back to roughly where it was in 2023. He 90th-percentile exit velocity hasn’t changed. His swing-happy approach will probably catch up with him at some point as pitchers adjust to it. Based on these metrics, I’m not sure we can convince ourselves that Polanco is an entirely new hitter.

That said, I love his swing changes. I don’t care as much about whether or not he has an open stance, but I love that he was able to simplify his swing so much without sacrificing any bat speed. I think that’s great and it really could be affecting his bat path, helping him go out and attack the ball and contributing to all those squared-up baseballs and line drives. I really hope Polanco holds onto these gains, and I also hope he sees a similar improvement from the right side once he’s fully healthy. But I think we’re going to need a bigger sample size before we decide if that’s likely to happen.