The best of BP 2025: A little over the line | Baseball prospectus

Translated by José M. Hernández Lagunes

There was, believe me, a time before the Internet. If you wanted to keep up with the news, you had to listen to the radio, watch television or read a newspaper or magazine. If you followed baseball, the newspaper was the only place you could find daily updates on statistics and standings.

And if you wanted a more complete list of baseball statistics than the occasional top 10 list in a category you’re interested in, you had to wait for the Sunday paper. There, buried in the sports section, they published a list of batting statistics (at bats, runs scored, hits, home runs, runs batted in and batting average) about teams and batters with more than a certain number of at bats. They were ordered on average. For pitchers, in the ERA series, you got innings, hits, walks, strikeouts, wins, losses, and ERA, first for teams and then for all pitchers above the decision threshold (not per inning!). Here is a rather illegible example of the diary Gainesville Sun of July 10, 1983.

Sorry how hard it is to see them. But you get the idea. For Baseball prospectus, FanGraph, Baseball referenceMLB.com and other sites, the place to get complete baseball stats was the Sunday paper. He Sporty news I had them too, but you had to wait until they arrived at the newsstand or until they arrived in your mailbox. The Sunday newspaper was immediately available: it contained everything for the games on Friday evening!

In the American League, the aforementioned best hitter was Rod Carewof the California Angels, with a batting average of .403 at that point in the season. (He would finish with a batting average of .339, second only to Wade Boggs). Sat on the other side Julio Cruzfrom Chicago, with a batting average of .234. However, the SunDue to lack of space, the list was removed. Gorman Thomasfrom Cleveland, for example, hit .191, but did not appear on the list. It didn’t appear either Tom Brunanskyfrom Minnesota, with a batting average of .199. Newspapers in larger cities, with more column space, carry more names. So while Thomas and Brunansky weren’t mentioned in Gainesville, they did appear in the newspapers of the cities where the teams play. And the players saw the statistics, just like the fans.

In 1979, short stop in Seattle Mario Mendozawas at the bottom of those lists. On May 13 of that year, the Sunday papers published his batting average at .202. It was .189 the next two Sundays, .186 the following week, and .185 in the papers on Sunday, June 10. (He finished the season with a .198 average.)

Bruce BendMendoza’s teammate with the Mariners, coined the term “Mendoza Line,” which referred to the batting average of the light-hitting shortstop. If your batting average was worse then Mario Mendozaat the bottom of the list on Sunday you were below the Mendoza line. When Kansas City traveled to Seattle for a four-game series beginning May 14, Mariners reportedly left center fielder, Tom Paciorekwarned George Brettof the Royals, who were in danger of falling under the Mendoza line. (Brett was hitting just .257 at the time and entered the series with an 8-for-38 slump. He went 6-for-16 in the series and finished the year with a .329 average.) Brett told ESPN host Chris Berman, and the term entered the baseball lexicon. (Mendoza, by the way, ended his MLB career in 1982 with the Rangers, returning to his native Mexico, where he played for seven more years, and was eventually inducted into the Mexican Baseball Hall of Fame in 2000.)

The Mendoza Line represents a batting average of .200. If you get below .200 like they did Bo Naylor (.195) y Michael Conforto (.199) Among players with at least 400 plate appearances this year, you would be below the Mendoza line.

Of course, 1979 was almost half a century ago. At the time, Sunday newspapers published batting averages because that was how batters were judged. We’ve come a long way since then. So at the suggestion of my friend José Hernández Lagunes, editor of BP in Spanish, I set out to define a new standard for ineffective hitting.

As you probably know, Bill James has pointed out that teams’ on-base percentage correlates much better with their run production than with their batting average. I discovered that while James’ observation was true at the time he wrote it, slugging percentage has exceeded OBP in recent years. Here are the correlations between a team’s runs and five commonly used batting metrics for 810 team seasons in the 30-team era (since 1998), excluding 2020.

Slug percentage has the advantage of being easy to calculate (just two numbers: total bases and at-bats). But OPS and wOBA have better correlations. The problem is that not all fans know what OPS and wOBA are, like they know AVG or even SLG. However, OPS is mentioned more often in broadcasts and articles than wOBA, so if we’re going to use a simple rule of thumb for the audience, I think it’s best to use the better known figure, even if it is slightly less accurate than wOBA.

The question then becomes: What do we use for the OPS equivalent of a .200 batting average? Specifically: What easy-to-remember value for OPS yields a level below which almost no one falls (but some do)?

I looked at the different OPS levels in the five post-pandemic seasons and the number of players with at least 400 plate appearances who fell short of that mark.

Obviously .550 is too low. (The three players with an OPS under .550 in the last five years are Jackie Bradley Jr. (2021, .497), Nick Allen (2025, .535) j Geraldo Perdomo (2022, fourth in NL MVP voting three years later, .547). For the same reason, .650 covers too much.

Take half of that distribution. The best number in my opinion is .590: on average only two or three players, but almost never zero. It is an achievable standard, although undesirable. But .590 is an awkward number; .600, a nice round number, is not. So let’s go with .600. Any OPS under .600 is below… wait, we need to find a name for the rule!

The first player I thought of was Allen. He is the modern Mendoza: good glove in the box, chewing gum stick. The problem is that he has taken the issue of güango tolete to the extreme. He never had an OPS higher than .600. He hasn’t even posted an OPS above .550. His lifetime average is .536. Mendoza’s career batting average was .215. A batting average under .200 can be named after someone with a batting average of .215. You can’t mention an OPS of less than .600 after someone who has never come close to that level.

Among active players with at least 1,000 plate appearances are the players closest to .600 Taylor Walls (.584), Sandy Leon (.585), Lucas Maile (.597), Billy Hamilton (.617) and Martín Maldonado (.620). The problem with that quintet is that Walls is more of a utility player than a regular player, and the others are nearing the end of their careers. Something about Walls’ line and Maile’s line sounds good, but it may not be.

There’s one more thing (bonus points if you understand the reference). Jonah Heim To be clear, he is a useful player. In 2023, he still generated 4.1 WARP thanks to a .259/.318/.439 offensive line, 18 home runs, 95 RBI and 17.1 defensive runs prevented. He fits in well with his mascot, and while his arm isn’t the best, he’s been good enough to deter base stealers. Overall, he has generated 9.1 WARP in just under five full seasons, always above replacement level.

But his play has gotten worse since 2023. His defense hasn’t been all that solid, and in fact, his OPS has been identical at .602 in both 2024 and 2025. Almost exactly .600. And no matter how beautiful the Walls Line or the Maile Line are, they cannot compete with the Heim Line. It sounds like “hemline“o”timeline“! ¡Rima!

This is our 21st century analogue to the Mendoza Line. This year, Nick Allen (.535), Joey Ortiz (.593) and Ke’Bryan Hayes (.595) had an OPS below .600.

They were under the Heimlinie.

Well, that’s what it’s called.