“I’ll start with the easy answer,” Jeff Zimmerman wrote in 2014. The next part was in bold: “No, stats in the first and second half are not as important as the entire season for pitchers and hitters.” Jeff was talking about fantasy baseball, and whether you should consider a particularly strong or weak second half more relevant to a player’s future performance, but the lesson was clear. General statistics tell you a lot more about a player than half a season’s worth of statistics.
The same lesson applies to the course of a career. Since 1933, the year of the first All-Star Game, Stathead says 2,146 players have made at least 900 career appearances in both the first and second halves. Just under 93% of these players have a second-half OPS that is within 10% of their first-half OPS. (We’re using percentages here instead of raw points to create a level playing field for players of different skill levels. I calculated them by subtracting each player’s OPS in the first half from the OPS for the second half and then dividing the difference by the OPS for the first half.) Only 15 players – again, that’s 15 players out of a sample of 2,146 – saw their OPS for the second half differ by more than 20% from their OPS for the first half.
This all makes sense. There is no reason that a hitter should be consistently better at the beginning or end of the season. As Eno Sarris once reminded us, seasons themselves are arbitrary endings. Most of the fifteen outliers I mentioned in the previous section are the result of short, noisy samples, either because they had short careers or are still in the early stages of their careers. The longer your career, the more likely your true talent level will shine through, regardless of the date on the calendar.
Today, there is even less reason for players to be fast or slow starters. There was once a time when players had to take off-season jobs at the slaughterhouse back home in Fargo to make ends meet White Ford told anyone who would listen that the secret was to looking like you were staying in shape during the winter get nice and brown. Nowadays everyone trains all year round and works with professional trainers and nutritionists. No one has ever been this far from playing form at the start of the year, and no one has ever had better maintenance during the season. Players spend their offseasons in the gym and the cages, and they spend the regular season drinking personalized recovery smoothies and resting in sleep pods.
For example, Elly Dela Cruz has huge splits, with a 128 wRC+ in the first half and an 84 wRC+ in the second half. However, he only played three seasons. He made an electric debut in 2023 before collapsing halfway through widespread reports by fatigue. In 2025 he played through an injury and the death of his sister in the second half. It’s possible that De La Cruz will remain a good starter and slow finisher. He plays the game at a million miles an hour, taking the extra base, stealing and laying out. Maybe he will always mess up the second half a little more than the average player. But for now it is far too early to say anything about that. He seems poised for a long career, and at some point things will likely even out. (As for whether there is a correlation between base stealing and the second half decline, I would note that Rickey Henderson had better numbers for the first half, but Lou Brock And Tim Raines were better in the second half. Even Cal Ripken Jr.who punished his body more than anyone, only saw his OPS drop by 25 points in the second half.)
I doubt I’m telling you something you don’t know, but here’s a scatterplot showing what we’re talking about. The more you play, the less likely you are to get big splits. (The scatter plot shows the absolute value of the difference, ignoring whether a player was better or worse in the first half.)
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To set yourself apart from the great right triangle of standard deviations, you have to play long enough to reach 10,000 plate appearances, and the vast majority of players who do that are Hall of Famers. It’s certainly possible that some players are slow starters and some players tend to get into trouble in the second half, but the sample size needed to definitively prove this is simply too large. So it’s all a lot of nonsense. To emphasize that house again, I’d like to end by talking about two of the widest points on that scatter chart.
See that red dot all the way out at 30%? That is Michael Harris IIwho has a career wRC+ of 80 in the first half and 134 in the second half. It’s a shockingly big difference. Harris is barely playable in the first half. In the second, he is one of the better hitters in baseball. Obviously we are talking about a small sample size here. Harris has only played four seasons, and the biggest statistical difference between his first and second half numbers is a 60-point jump in BABIP. Yet he is alone. I’m willing to bet that things will even out somewhat over the course of his career, but after this start he’ll almost certainly end up with a pretty big break when he retires. And if this is exactly what he does every year, I can’t wait to read the 2026 version of the article explaining how he turned things all around mid year.
Julio Rodriguez is that other red dot all the way to the right. He’s not as extreme as Harris – no one is as extreme as Harris! Rodríguez has also never been bad at the plate, even in the first half. He has a career wRC+ of 114 in the first half and 154 in the second half. Most players would be happy with a 114 wRC+ at any point in the season, but a 40-point difference is still very extreme. It’s even stranger when you note that all four of his IL stints have come during the second half instead of the first. Maybe he’s just a slow starter. Maybe both guys should get up early to avoid their dreaded slow starts. Right? Wrong.
Harris and Rodríguez start every year well! We have spring training numbers going back to 2006, and if you set a minimum of 60 at-bats, you get a sample size of 2,482 players. Rodríguez’s 174 wRC+ is the 13th best mark in the last 20 years! Harris isn’t at the very top of the leaderboard, but he has a career wRC+ of 136, better than his second-half numbers. The rollercoaster is even wilder for Harris, who is also just 6-for-35 in the postseason for a paltry 24 wRC+. To explain it all clearly:
Spring training: He’s great.
First half: He’s terrible.
Second half: He’s great.
Postseason: He’s miserable.
I told you it was nonsense.
#Fun #Meaningless #Splits #Edition