Best of BP 2025: One Poke Over the Line

There was, trust me, a time before the internet. If you wanted to catch up on news, you had to listen to the radio, watch TV, or read a newspaper or magazine. Specifically, if you followed baseball, the newspaper was the only place you could get daily updates on box scores and standings.

And if you wanted a more comprehensive list of baseball statistics than an occasional top-ten list, you had to wait for the Sunday paper. There, buried in the sports section, there’d be a list of batting statistics (at-bats, runs, hits, home runs, RBI, and batting average) for teams and for batters with more than a set number of at-bats. They’d be ordered by average. For pitchers, in ERA sequence, you’d get innings pitched, hits, walks, strikeouts, wins, losses, and ERA, first for teams, then for all pitchers above a decision (not inning!) threshold. Here’s a pretty illegible sample from the Gainesville Sun on July 10, 1983.

Sorry that’s so hard to read. But you get the idea. Before Baseball Prospectus, FanGraphs, Baseball Reference, MLB.com, and elsewhere, the place to get comprehensive baseball stats was the Sunday paper. The Sporting News had them, too, but you had to wait for it to hit the newsstand or get delivered to your mailbox. The Sunday paper was immediate: It had everything through Friday night’s games!

In the American League, the leading hitter listed above was California’s Rod Carew, batting .403 at that point in the season. (He’d finish at .339, second to Wade Boggs’ .361.) At the other extreme was Chicago’s Julio Cruz, .234. However, the Sun, for space limitations, cut off the list. Cleveland’s Gorman Thomas, for example, was batting .191 but didn’t get listed. Neither did Minnesota’s Tom Brunansky, .199.

Bigger-city newspapers, with more column inches to spare, listed more names. So while Thomas and Brunansky didn’t get mentioned in Gainesville, they were in papers in the cities where teams play. And the players saw the numbers, just like the fans.

In 1979, Seattle shortstop Mario Mendoza found himself at or near the bottom of those lists. The Sunday papers on May 13 that year listed his batting average as .202. It was .189 the next two Sundays, .186 the week after that, then .185 in the papers of Sunday, June 10. (He finished the season at .198.)

Mendoza’s Mariners teammate Bruce Bochte coined the term “Mendoza Line,” indicating the light-hitting shortstop’s batting average. If you were worse than Mario Mendoza, at the bottom of the list on Sunday, you were below the Mendoza Line.

Supposedly, when Kansas City traveled to Seattle for a four-game series beginning on May 14, Mariners left fielder Tom Paciorek warned the Royals’ George Brett that he was at risk of falling below the Mendoza Line. (Brett was hitting just .257 at the time, entering the series in an 8-for-38 slump. He went 6-for-16 in the series and finished the year at .329.) Brett mentioned it to ESPN SportsCenter host Chris Berman, and the term entered baseball’s lexicon.

(Mendoza, incidentally, finished his MLB career in 1982 with the Rangers, returned to his native Mexico, where he played for seven years, and was inducted into the Salón de la Fama de Beisbol Mexicano, the Mexican Hall of Fame, in 2000.)

The Mendoza Line has come to represent a .200 batting average. If you bat below .200, as did Bo Naylor (.195) and Michael Conforto (.199) among players with at least 400 plate appearances this year, you’re said to be below the Mendoza Line.

Of course, 1979 was nearly a half-century ago. Back then, the Sunday papers listed batting averages, because that’s how batters were evaluated. We’ve come a long way from then. So, at the suggestion of my friend José Hernández, editor of BP en español, I set out to define a new standard for ineffective batting.

As you probably know, Bill James noted that teams’ on-base percentage is much better-correlated to their run production than their batting average. I found that while James’ observation was true at the time he wrote it, slugging percentage has surpassed OBP in recent years. Here are the correlations between team runs and five commonly-used batting measures for the 810 team-seasons in the 30-team (beginning in 1998) era, excluding 2020.

Metric	Correlation
AVG	0.73
OBP	0.86
SLG	0.91
OPS	0.95
wOBA	0.97

Slugging 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, not all fans know what OPS and wOBA are the way they know AVG or even SLG. But OPS gets mentioned on broadcasts and in articles more often than wOBA, so if we’re going to go with a simple rule of thumb for the public, I think it’s better to use the more familiar figure, even if it’s a little shy of the precision of 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 that almost nobody falls below (but a few do)?

I looked at various OPS levels in the five post-pandemic seasons and the number of players with at least 400 plate appearances who failed to achieve them.

Number of Players with OPS Below	2021	2022	2023	2024	2025	Average
.650	13	28	15	26	17	19.6
.640	10	22	11	18	15	15.2
.630	9	18	11	13	10	12.2
.620	7	12	11	7	7	8.8
.610	5	10	7	2	7	6.2
.600	4	7	5	0	3	3.8
.590	4	7	2	0	1	2.8
.580	4	5	0	0	1	2.0
.570	2	5	0	0	1	1.6
.560	2	3	0	0	1	1.2
.550	1	1	0	0	1	0.6

Clearly, .550 is too low. (The three players to have an OPS below .550 in the past five years are 2021 Jackie Bradley Jr. (.497), 2025 Nick Allen (.535), and 2022 Geraldo Perdomo (fourth in the NL MVP vote three years later—.547). By the same token, .650 casts way too wide a net.

Consider the middle of that distribution. The best figure, I think, is .590: just two or three players on average, but hardly ever zero. It’s an achievable, if undesirable, standard. But .590 is a clunky number. .600, a nice round number, isn’t. So let’s go with .600. Any OPS below .600 is below the…wait, we’ve got to come up with a name for the line!

The first player I thought of was Allen. He’s the modern Mendoza: Good field, no hit infielder. The problem is, he’s taken the no-hit thing to an extreme. He’s never had an OPS above .600. He’s never even had an OPS above .550. His career average is .536. Mendoza’s career batting average was .215. You can name a sub-.200 batting average after a guy with a .215 career figure. You can’t name a sub-.600 OPS after a guy who’s never come close to that level.

Among active players with at least 1,000 plate appearances, those closest to .600 are Taylor Walls (.584), Sandy León (.585), Luke Maile (.597), Billy Hamilton (.617), and Martín Maldonado (.620). The problem with that quintet is that Walls is more a utility guy than a regular and the others are near the end of their careers. Something about the Walls Line and the Maile Line sounds good, but may not be right.

There is another. (Bonus points if you get the reference.) Jonah Heim is, to be clear, a useful player. As recently as 2023, he generated 4.1 WARP on the strength of a .259/.318/.439 slash line, 18 homers, 95 RBI, and 17.1 defensive runs prevented. He’s been a pretty good framer, and while his arm isn’t the best, it’s been good enough to deter basestealers. All told, he’s generated 9.1 WARP over a little under five full seasons, always above replacement level.

But his game’s regressed since 2023. His defense hasn’t been as strong, and, more to the point here, his OPS has been an identical .602 in both 2024 and 2025. Almost .600 on the nose. And as pleasing to the ear as the Walls Line or the Maile Line might be, it can’t compete with the Heim Line. It sounds sort of like hemline or timeline! It rhymes!

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

They were below the Heim Line.

Make it so.