For Willie Mays, it’s the one that got away.

As Major League Baseball officially incorporates verified Negro Leagues statistics into its official record, the great Mays, who suited up for the 1948 Birmingham Black Barons, gets 10 hits added to his ledger, bringing him to 3,293.

But Mays’ career home run total remains at 660.

Not because he didn’t go deep for the Black Barons, but because there are no box scores available from when he did go deep.

“Baseball is a double-entry account system in which every action of the offense is mirrored by an action of the defense,” explained John Thorn, MLB’s official historian and chairperson of the Negro Leagues Statistical Review Committee. “An out registered by a batter must be secured in the field as well. So in absence of a box score, we cannot be sure that the Negro Leagues records will balance, and balance is the essence of the game.”

On Aug. 11, 1948, Mays, just 17 years old and about to begin his junior year at Fairfield (Ala.) Industrial High School, hit a home run to left field in a game against the Cleveland Buckeyes at Alberta Park in Tuscaloosa. We know this to be true, because the home run was chronicled in both the Birmingham News and the Alabama Citizen.

“The Black Barons tagged [Webbo] Clarke for 11 hits,” read the next day’s Birmingham News account, “including a homer by Willie Mays in the second inning.”

To complete what is being called “Version 1.0” of the process of incorporating Negro Leagues stats into the official register, the Negro Leagues Statistical Review Committee worked with Retrosheet to verify the statistical database assembled by Seamheads.com. Researchers estimate the available data from the relevant Negro Leagues from 1920-1948 to be roughly 80 to 85% complete.

But as Thorn explained, without a box score, there is no way to statistically account for Mays’ “661st” home run ... or another one Retrosheet lists for him on Aug. 28 of that season. The Lexington Herald reported that Mays hit a three-run shot against the New York Cubans at Blue Grass Field in Lexington, Ky.

Should box scores eventually surface from one or both of those home runs, Mays’ official tally can be updated. In announcing the inclusion of the Negro Leagues numbers, MLB made it clear that “future findings may result in additional modifications of the game’s all-time leaderboards.”

But for now, the absence of the box scores is a bit of a buzzkill.

Same goes, by the way, for the legendary Josh Gibson’s oft-mentioned four-homer game during his 1938 season with the Homestead Grays. Reporting on the Grays’ 17-4 victory over the Memphis Red Sox on July 28, 1938, the Zanesville (Ohio) Signal wrote the following:

“Gibson, regular catcher for the Homestead club, was sent to right field and during the encounter cracked four home runs. In a season, Gibson collected an average of 10 four-baggers per week.”

Gibson will have to settle for being listed as MLB’s new all-time and single-season leader in the batting average, slugging percentage and OPS categories following this update.

As for Mays, barring a box score find, he’s stuck at 660 homers, which is still good for sixth all-time behind Barry Bonds (762), Hank Aaron (755), Babe Ruth (714), Albert Pujols (703) and Alex Rodriguez (696).