Did the Giants juice the radar gun in this legendary Barry Bonds at-bat?

Late in the night of April 16, 2004, Barry Bonds dug in against Dodgers closer Eric Gagne with a man on first base. It was the bottom of the ninth, and the Giants trailed 3-0.

The two players were at the height of their powers. In 2003, Gagne won the Cy Young with a 1.20 ERA in one of the most offensive-friendly environments in baseball history. Bonds, of course, would go on to post a 1.421 OPS in the 2004 season, walking in 37.6% of his plate appearances.

Save for an 0-2 curveball pitch, Gagne went to his fastball for each of the seven pitches. After blasting the sixth pitch foul into McCovey Cove, Bonds took Gagne deep to center on the seventh. Ultimately, the result didn't matter. Gagne retired the next two hitters, and the Dodgers won 3-2 in a relatively meaningless regular season contest. But the at-bat has lived on in the memory of fans, appearing apropos of nothing in blog posts over the last decade-and-a-half. It likely has to do with the symbolism of it all: two players, both of whom used performance-enhancing drugs in their playing days, perfectly personifying an era of baseball characterized by cartoonish power.

But it's also due to two rumors long connected to the showdown. In one rumor, Gagne and Bonds had agreed to a bet that Gagne would only throw heaters in their next match-up. In an interview at the SABR Analytics Conference in 2018, Gagne mostly confirmed the veracity of this rumor.

"We were in Japan on an all-star tour [in 2002] and Barry always complained about [nobody giving him pitches to hit]," Gagne said. "I said, ‘You know what, if I get a 3-run lead one time and I come in, I’ll face you, I promise. … He said, ‘All right. All fastballs?’ I said, ‘Uhh, no, not all fastballs. I can use one off-speed.’ He said, ‘Perfect. But no changeups.’"

In another rumor, the Giants were intentionally displaying artificially high readings from the stadium radar gun on the scoreboard to goad Gagne into throwing more fastballs to Bonds. In the video of Bonds' at-bat, the announcers can be heard remarking that the stadium gun is a couple miles an hour faster than the one displayed on television.

"I don't throw that hard," Gagne told reporters the day after the game. "I throw 96, 97, maybe 98 on a good day. But 102? No way. I think they were pumping them up a bit. They wanted me to throw a fastball probably."

At the time, the Giants denied the rumor, saying the stadium gun is calibrated by a computer and not a human. But on Twitter last night, the San Francisco Chronicle's beat reporter Henry Schulman revived the long-dormant controversy, appearing to corroborate the truth of Gagne's accusation.

"An at-bat in which, before Statcast and standardized radar guns, the #SFGiants had their stadium folks add several mph to Gagne’s fastball on the scoreboard to convince him he was throwing harder than he was so he’d keep feeding Bonds fastballs and not go off speed," Schulman wrote. "It worked."

So what's the truth? Both rumors could be true, and evidently, there could be even more to this wild story. In a reply to Schulman, former Giants reliever David Aardsma wrote, "I watched this from the dugout. There is a huge backstory." He did not elaborate.

Perhaps we will dive down this rabbit hole for the rest of time. For the time being, however, it's a good excuse as any to reflect on the greatness of Barry Bonds, a player whose dominance will never again be matched.

Michael Rosen is an SFGATE digital editor. Email: michael.rosen@sfgate.com.