For the second year in a row Jewish Heritage Day has belonged to first baseman Mike Jacobs.

On August 21, 2005, the California native electrified the hometown New York Mets fans when he was called up from the minors as a pinch hitter in the fifth inning of a game against the Washington Nationals and hit a three-run home run on his first swing in the Major Leagues. That day happened to be Shea Stadium’s Jewish Heritage Day, and the heavily Jewish crowd of 42,000 erupted in a frenzy of deafening cheers. (The homer wasn’t enough to save the Mets from a 7-4 loss.)

Then, late last month, Jacobs’s new team, the Florida Marlins, celebrated its own Jewish Heritage Day at Dolphin Stadium and handed out free T-shirts featuring his name and jersey number.

“The Marlins thought they were honoring their Jewish first baseman” by celebrating him that day, the Palm Beach Post wrote. “One small problem — Jacobs isn’t Jewish, a fact the Marlins would have learned if they’d asked Jacobs himself.”

This wouldn’t be the first time that a non-Jewish ballplayer with a Jewish-sounding name had been taken for the genuine article, according to Martin Abramowitz, the amateur baseball historian behind the commemorative 142-card set “America’s Jews in America’s Game.”

“David Eckstein, Gabe Gross, Mike Mordecai,” Abramowitz said, rattling off a list of players that have at one time or another been falsely identified as Jewish.

But Jacobs appears to be in a class by himself.

The Marlins’ front office is denying any connection between Jewish Heritage Day and the T-shirt giveaway, which both took place in conjunction with the Marlins’ May 28 game against — of all teams — the Mets. “There’s no correlation between the two. Absolutely none,” the team’s vice president of marketing, Sean Flynn, told The Associated Press. “We have a lot of promotions, sometimes on the same day, and they don’t necessarily have to be related to one another.”

Perhaps. But as local observers pointed out, the Jacobs T-shirt giveaway had been hyped days before the game in a full-page advertisement in a local Jewish newspaper. And Jacobs has had a relatively lackluster season — with a less-than-respectable .236 batting average — that otherwise wouldn’t seem to merit special attention.

For his part, the rookie infielder seems to be taking all the confusion in stride. “I don’t know what happened,” Jacobs told AP. “They told me there was no connection. It’s not a big deal. It’s just a misunderstanding.”