What Should We Make of Jesse Winker?

Here is an understatement: Jesse Winker had a pretty solid weekend. On Friday, he collected four hits, including three home runs, and a walk. On Saturday, he only went 1-for-4, but added another homer. And on Sunday, he homered again, bringing his weekend total to five and his season total to 13. His wRC+, which entered the weekend at a cool 166, jumped 26 points to 192; by this metric, he’s now the third-best hitter in baseball. His .463 wOBA, meanwhile, ranks first.

To say that Winker has broken out this season would be inaccurate. He has always been a very good hitter, particularly against right-handed pitching. Plus, his numbers have seen a significant uptick over a fairly large sample. In short, it’s not just 2021: Over his last 162 games, dating back to May 22, 2019, he is hitting .306/.401/.563 with 31 homers. In that span, he has been the seventh-best hitter in the majors by wRC+, at 154.

He really put everything together during his 2020 season, with his once-extreme platoon splits (we’ll get to those in a moment) dissipating in the shortened campaign. His 146 wRC+ was a “seasonal” career-high, and his .289 ISO was eye-popping for a hitter who had posted sub-.200 marks for his career to that point. Winker, who had rarely been considered a power hitter — he graded as having 30 game power in his last prospect scouting report back in 2018 — posted the same 2020 ISO as Teoscar Hernández.

Winker’s 2020 season did turn heads, as did his hot start to 2021. But we’re admittedly still dealing with small-ish samples for this new slugging version of him. His ISO, which was only .181 going into 2020, is .320 so far this season. And we’re starting to see the projection systems more fully buy in. Here are the largest rest-of-season ZiPS ISO increases, compared to the pre-season projections:

ZiPS was admittedly the lowest on Winker’s power potential prior to the season, with other systems seeing his ISO as high as .214. But with each plate appearance that he maintains his slugger ways, the projection systems will have to adjust further. And they’ve already had to make a huge adjustment relative to other players. More than the exact figure itself, the increase shows just how good Winker has been.

There’s plenty of reason to think that .213 is still on the low end for his rest-of-season figure, though regression is certainly going to come regardless. Winker’s .355/.412/.684 slash line is buoyed by a .389 BABIP, and his expected ISO (xSLG minus xBA) of .280 is nearly 50 points below his actual .329 figure. It does help that Winker plays for the Reds, as Great American Ballpark is the most homer-friendly stadium for left-handed hitters in baseball. In the Statcast era, Reds lefties are tied for the second-largest margin in the majors in terms of outperforming their xSLG at home, with only Rockies lefties doing better:

Winker doesn’t have the most extreme home-road splits (147 wRC+ at home versus 124 wRC+ on the road), but there is certainly a noticeable difference in his power numbers there, with an ISO that is 60 points higher at GABP than it is elsewhere. And since powering up at the beginning of the 2020 season, that gap has grown, although both his home and road ISO figures are much higher than they were for his career pre-2020.

Here are Winker’s home splits:

And now here are his road splits:

Clearly, Winker is a very good hitter everywhere he plays, but the ISO gap is noticeable. Prior to 2020, there was only a 42-point difference between his ISO at home and on the road, suggesting that while he did hit for more power at home thanks to GABP, it wasn’t an enormous difference. Since then, however, the gap between his home and road ISO has jumped to 94 points. That may sound like a lot, but it is not egregious when viewed in the context of the rest of the league, as hitters typically hit for more power at home. Using a simple linear regression, Winker’s expected road ISO (.241) based on his home ISO would actually be lower than his current road ISO (.257); he’s actually hit for slightly more power on the road than would be expected. You can see this trend line in the following scatterplot:

Then there’s the question of platoon splits — what might hold Winker back from ever becoming one of the most complete hitters in the game. He’s done a decent job of hiding it over the last couple of seasons, perhaps suggesting that he’ll become more serviceable against lefties, but handedness splits take a long time to stabilize, and his full body of work shows an ugly hole in his game:

Clearly, one of the main reasons Winker’s career numbers look so good is that 81% of his plate appearances have come against right-handed pitching, which he crushes. This is noticeably more, but not wildly more, of a platoon playing-time split than the average hitter, who has faced right-handers 73% of the time since the beginning of 2017, Winker’s first season. But it makes you wonder just how good he could be with even league-average numbers against lefties. Since the beginning of 2017, he has the fourth-largest handedness split of any player in the game by wRC+:

There is recent evidence that Winker may be shoring up his performance against left-handed pitching, but it’s hard to know if that’s real or just noise in a small sample. This season, Winker has a 217 wRC+ (!) against righties but just a 97 wRC+ against southpaws, to go along with a 257-point ISO platoon difference (.382 versus .125). Last season, meanwhile, he had almost no platoon difference, at least in terms of wRC+ (148 versus 140). But that is likely the result of a .368 BABIP against left-handed pitching in a mere 41 plate appearances. Winker doesn’t hit nearly as well if a left-hander is on the hill, but since a righty is pitching most of the time, and the Reds have done some extra shielding of him against lefties, the overall slash line looks sterling.

This leaves us with an interesting question: What to make of Jesse Winker? I do think he is one of the best hitters in baseball; the numbers reflect that, and his statistical performance has come in a large enough sample to back me up. The platoon splits can be presented as an argument against that: How can you call someone one of the best hitters in baseball if he doesn’t perform against pitchers of both handedness? But with the vast majority of his plate appearances coming against righties, plus some extra platoon savviness by the Reds, I don’t have an issue saying that Winker has turned himself into one of the better, if not best, hitters in the game.