Seinfeld even managed to sneak in swipes at Lady Gaga ("I'm sure we'll all be bigger fans now that she's cursed us out.") and Select Sector Spdrs, which sponsors rain delays at Citi Field ("Whenever fans are unhappy, disappointed, their game's interrupted, we want our logo up there.").
Seinfeld first met Hernandez in 1992 on the set of his show when they filmed "The Boyfriend," the classic episode in which the retired first baseman was a potential friend for Jerry and boyfriend for Elaine. Seinfeld said the role was written specifically for Hernandez, calling him the "perfect guy" for the part.
"I was most excited to meet Keith Hernandez of anyone I ever met on the show," Seinfeld said. "I wanted him to have a good experience. ... I was still in the glow of '86."
Hernandez himself said it was a nerve-racking experience and that he "botched" a few takes of his kiss with Elaine, played by Julia Louis-Dreyfus.
Seinfeld forgave Hernandez for that and for getting caught falling asleep in the booth last month.
"There's nothing wrong with falling asleep on the job," he said. "When a guy's head hits the desk, you know you're getting everything out of him."
"At least he didn't sleep under the desk like Costanza," Cohen deadpanned, referring to "The Nap," an episode in which the character George Costanza -- played by Jason Alexander -- starts taking naps in the space beneath his desk at work. Seinfeld added that George, who worked for the Yankees during several of the series' seasons, could never have worked for the Mets.
After going over the episode, Seinfeld delved into Mets history with Cohen and Hernandez, two experts in the field. The three all revealed their favorite moments in the history of the franchise, with Seinfeld selecting Endy Chavez's catch in Game 7 of the 2006 National League Championship Series.
"In that moment, it was a remarkable catch," he said. "We literally jumped out of our seats. We couldn't believe he made the catch."
Seinfeld also said his favorite Met of all-time is Tommie Agee, whom he called "our Willie Mays." Agee, of course, was one of heroes of the 1969 Miracle Mets, making two astonishing catches himself and hitting a leadoff home run in Game 3 of that World Series. He also fondly recalled the methodical walk of former manager Gil Hodges.
"I don't think there's anything more fun than being a Mets fan," Seinfeld said. "They have two world championships, but they're two as exciting as you could have."
Hernandez was impressed by Seinfeld's baseball knowledge.
"We wanted to get him to talk about the show, but he just wanted to do the game," Hernandez said afterward. "It was great to have him in there. It was a great experience."
SNY complemented Seinfeld's cameo with clips from "The Boyfriend," including Hernandez's talking himself into kissing Elaine by reminding himself that he "won the MVP in '79!" Sideline reporter Kevin Burkhardt reported that the Mets' clubhouse thought Jason Bay could have played Jerry and Jeff Francoeur would have made for a good Kramer on the show. And the network's text poll asked if Jerry was right to turn down Hernandez's request to help him move on the episode. (For the record, 52 percent voted "Yes.")
Seinfeld departed during the seventh-inning stretch, paying more compliments to "the greatest booth in baseball" and thanking SNY.
"This was an honor," he said. "This was really an honor to be part of your booth."