One of the more popular exercises after every season is to look at players with significant variance between their first and second halves. Given the sample sizes, this can be a very useful way to evaluate players, often better than looking at the season as a whole. Injury, luck, mechanical adjustments, and a host of other factors can impact individual halves, distorting the statistics over a full season. Breaking down each part of the year can reveal much about players, providing valuable information for the following campaign.

But many forget that this process is just as useful during the season. Taking a look at first and second half performance doesn’t need to be restricted to a full season—it can also be done in a more limited size, such as the first half alone.

With this in mind, I compared every player in the league between a so-called ‘first’ and ‘second’ half, split up May 22^nd, or the midpoint in the season thus far. I gathered the twenty players with the biggest positive changes in their batting average and slugging percentage, and noticed they fit into four basic groups (considering the sheer number of players involved in this, I’m going to make the article two parts, each involving two of these ‘groups’). Without further ado, here are those aforementioned players.

*Note: for simplicity, in this article “first half”=April 1^st to May 22^nd, “second half”=May 22^nd to July 14^th

Group One: Absurdly bad first half, absurdly good second half

Peter Bourjos, .212/.305 vs. .350/.553

Mr. Bourjos owns a career .246/.303/.386 line, hit .410 in June, and had a .424 BABIP from May 22^nd on. Honestly, there’s not a whole lot more you need to know. Bourjos used to have elite speed and defense, and was even worth 4.2 fWAR one year! Now, he has neither elite speed nor defense, but does have elite luck. Alas, that luck isn’t sustainable, and neither is Bourjos’ torrid ‘second half’.

Kendrys Morales, .190/.323 vs. .336/.606

Morales hadn’t been the same player since he broke his leg in the dogpile following his own walk off grand slam, but 2015 was one of the best seasons of his career. After a 47 wRC+ in the first half, it looked like his one-year resurgence was simply Royals devil magic. That wRC+ saw a 257% increase in the second half, though, and Morales hit twice as many home runs from May 22^nd on. The stark differences can partly be blamed on overly bad and good luck, but there’s more to this story.

For a good part of the early-season, it appeared there was something wrong with Morales’ hitting mechanics from the left side. A switch hitter, he was doing fine as a right handed hitter (against southpaws), but was nearly hopeless when he faced right handed pitchers. Considering there are far more right handed pitchers in baseball than left handed arms, this unsurprisingly sunk his performance. Luckily, Morales found the kink in his swing is once again able to hit righties. He’s now walking more, striking out less, and hitting the ball much harder. Some regression is to be expected, but Morales should continue to be a valuable bat in the middle of the Royals lineup.

Luis Valbuena, .197/.316 vs. .328/.606

How can someone hit .197/.288/.316 in his first 135 plate appearances, but still be a top-50 hitter on the season? Apart from the Dodgers discovering how to clone Clayton Kershaw and stalling offense league-wide, the only answer is a monster performance in June and July. Luis Valbuena has done just that, hitting .328/.423/.606 with a 171 wRC+ in the ‘second half.’ The 30-year old finally has had some batted ball luck go his way, allowing the big power to shine and batting average to follow.

Although Valbuena has gotten a bit too lucky recently and is striking out too much, he is hitting everything hard and pulling more than half of the pitches he makes contact with. This approach won’t work so seamlessly in the long run, but Valbuena has done some exciting stuff of late. We know the power is real, and there’s a chance Valbuena isn’t a black hole in the batting average (and on base percentage) department going forward. He’s not the best option to buy in the trade market, but riding this wave isn’t a bad idea.

Danny Espinosa, .206/.294 vs. 272/.603

Most dynasty owners hate Espinosa right about now, and it isn’t just because they’re jealous of his moustache. Espinosa decided to play like, well Danny Espinosa for a couple months, seemingly opening the door for Trea Turner. He then slammed it shut, hitting five home runs in nine days and a total of 11 since Turner’s demotion at the start of June. Espinosa still has a .239 average on the season, but needs just three more home runs to set a career-high (he’s currently at 18).

Espinosa is hitting more flyballs and pulling pitches, which are both conducive to a power uptick, but he probably hasn’t suddenly blossomed into a slugger. Decent pop and an average in ‘meh territory can be expected for the remainder of the season, which is rosterable in standard leagues (especially for a second baseman), but nothing to get too excited about.

Brian Dozier, .199/.318 vs. .283/.560

Dozier already has a close relationship to first/second half splits, as he’s always been a much better hitter earlier in the season. In the microcosm of 2016’s first half, though, he’s done the opposite. Dozier’s always been a liability in batting average, but he bottomed out with a sub-.200 mark with minimal power in the ‘first half.’ Luckily, Dozier made some hugely beneficial adjustments and has gone on a power surge in June and July.

Dozier, normally an extreme pull hitter, went away from his normal batted ball habits for a bit to start this season, though he’s regressed back to normal and results have followed. He’s making more hard contact, walking at a near-career high rate, and striking out less than ever before. There’s nothing ridiculous going on with his BABIP, so there’s reason to believe Dozier is not only back on track, but on his way to one of the better seasons of his career.

Group Two: Disappointing first half for a star, great second half

Anthony Rizzo, .234/.519 vs. .350/.643

Josh Donaldson, .250/.517 vs. .357/.690

Carlos Gonzalez, .264/.417 vs. .366/.680

Paul Goldschmidt, .245/.445 vs. .345/.571

Joey Votto, .205/.356 vs. .296/.526

I know, I know. Format changes halfway through an article aren’t really welcomed. I’m going to treat these five players as a group and run through things fairly quickly, though, because you probably already know what to think of them. All are bonafide fantasy (and real life) studs who encountered some bad luck or fluke-y performance early in the season but eventually (more than) righted the ship.

It’s still important to include Rizzo, Donaldson, Gonzalez, Goldschmidt, and Votto in this article, though, because currently their overall statlines don’t tell the whole story. The rough early season performances can be completely disregarded, and we can return to valuing these five players as the should be valued—some of the best hitters in the game.