After all, the lineup card can only accommodate one designated hitter at a time, and that is probably where both are ultimately headed.
Thankfully, that day hasn't arrived yet. In fact, Posada's days as an everyday DH are probably over Sunday, much to his delight.
On Saturday, the pair of future DHs formed about as potent a 1-2 punch as a 38-year-old catcher and a soon-to-be 36-year-old shortstop can.
Jeter and Posada, best friends and longtime teammates, combined for three home runs and eight RBIs in the Yankees' 9-3 win over the Houston Astros at Yankee Stadium. Combined with the solid pitching of Javier Vazquez, who threw seven strong innings for the third straight outing and won his fourth game in his last five starts, it made for an effortless day at the office for the home team.
And yet Posada will be happy to return to his old position, behind the plate, where bumps, bruises and cramping from doing 100-plus deep knee bends over a three-hour period are all part of the job description.
"You get banged up," he said, "but I enjoy it."
Asked before the game if he liked being the DH, Posada said, "No. Not at all. I don't know what to do with myself between at-bats."
Asked after the game if he wanted to amend that opinion, having hit a grand slam in the third inning -- the 250th homer of his career -- Posada was equally adamant.
"No," he said. "I still don't like it. It's tough. It's really tough for me."
Unlike a lot of players, who prefer to spend all their time thinking about their last at-bat or their next, Posada said he uses his time behind the plate as a refuge from hitting, a place to escape the mind games that hitters play on themselves, especially when things are not going well.
Since returning from the disabled list June 2 after missing 17 games with a hairline fracture of his right foot -- suffered, of course, while catching when a batter fouled a pitch down onto his foot -- Posada had started nine games at DH.
But without the safe haven of the mask, shin guards and chest protector, he had struggled, collecting just four hits in 33 at-bats. He had tried a multitude of diversions between at-bats to keep his head in the game but off his struggles: stretching, riding the exercise bike, strolling down to the weight room, watching videotape, even taking a few swings in the batting cage. But nothing seemed able to replace the tranquility of mind he said he achieves sitting behind the plate, handling a pitcher.
"You're so into the game, you don't think about your hitting," he said. "I miss that."
Saturday, the only thing he did differently was closely study the Astros starter, Wandy Rodriguez, from the bench rather than a video screen.
"I was watching what he was trying to do, getting ahead in the count and then throwing that curveball," Posada said. "Not that I was sitting on the curve, but I was trying to stay back and go to right field."
In the third inning with the bases loaded, Rodriguez followed the pattern Posada had picked up. He went ahead 0-1 on a fastball, then tried to sneak a curveball past. Posada, batting right-handed against the lefty, waited that extra millisecond, then drove the pitch into the right-field bleachers, clearing the bases and opening up a 6-2 Yankees lead.
For Posada, the shot was not special as a grand slam -- he had hit seven of them before, although not since 2004 -- but as a milestone shot in a career that is not yet over.
"Tell you the truth, it's not just another home run," he said. "It's meaningful. Not so many catchers get to be in that spot, so I'm happy to still be here and to do it."
In actuality, 237 of Posada's home runs were hit as a catcher, eight as a DH, four as a pinch-hitter and one as a first baseman.
Still, the total leaves him behind only nine catchers, and five of them -- Roy Campanella, Gary Carter, Yogi Berra, Johnny Bench and Carlton Fisk -- are in Cooperstown.
Returning to that fraternity -- catchers, that is -- is where Posada believes he belongs, even at an age when most of those guys had shifted to other positions. Or, nowadays, to DH.
"Unless he comes in [Sunday] and can't walk," Joe Girardi said, "he's gonna catch for us."
That brought a wider smile to Posada's face than the home run did.
"I'm happy, really happy," he said. "Nothing against [Francisco Cervelli]; he's done a great job. But I'm just glad to get a chance to get back out there again."
GAME NOTES: Posada's 250th homer tied Graig Nettles for seventh on the Yankees' all-time list. ... Jeter's two-HR day was the ninth of his career and first since 2006. His home run was the 24th leadoff HR of his career, tying him with Rickey Henderson for most in Yankees history. Henderson accomplished the feat in 567 leadoff at-bats, Jeter in 606. ... Vazquez (6-5) worked a tidy seven innings (six hits, three earned runs, six K's) despite never breaking 90 mph on the radar gun. Both he and Girardi agreed the upper 80s is a neighborhood he can live in as long as he continues to make good pitches in tough spots. "I see now when he gives up a base hit or a run, he stops it," Girardi said. "He's not carrying it over like he did before." Vazquez agreed: "When things aren't going so good and you get into trouble, you think, 'Uh-oh, here we go again.' I don't feel that way anymore." ... Marcus Thames left the game in the fifth inning with what the Yankees called a strain of the right hamstring. He went for an MRI, which came back "negative," whatever that means. ... In Thames' absence, Brett Gardner played left field and came to bat for the first time since leaving Tuesday's game in Baltimore with a strained ligament in his left thumb. Gardner went 0-for-2. ... Girardi said Alex Rodriguez, out of the lineup with tendinitis in his right hip flexor "felt better" on Saturday. No word on whether he would be available to play or pinch hit Sunday. ... Sunday's pitching matchup: RHP Phil Hughes (8-1, 2.71) vs. RHP Brian Moehler (0-2, 6.12).