His winning hit came only after the Mets placed Tejada on the DL, received an inefficient effort from starting pitcher Jon Niese, managed to tie the game against the great Roy Halladay and then endured yet another injury, this one to catcher Josh Thole. With all that as context with a 2-2 tie in the ninth, first baseman Ike Davis and backup catcher Mike Nickeas drew a one-out walk and hit a two-out double against Phillies closer Papelbon, respectively.
That brought up Valdespin, whom the Mets had recently optioned to Triple-A after an uneventful, 0-for-6 introduction to the Majors. Major League rules allowed the Mets to bring back Valdespin on short notice because of the injury to Tejada, who strained his quad in Sunday's series finale against the D-backs.
A middle infielder who has showcased both power and speed throughout his Minor League career, Valdespin took a called strike one before launching Papelbon's second pitch -- a sinker that the pitcher admitted "wasn't fully executed" -- well beyond the right-field fence. Valdespin pumped his fist multiple times as he rounded the bases, then descended into a mob in the visiting dugout.
"He can hit," Nickeas said. "You saw him do a little bit of it tonight. I've seen him do that, amongst other things."
The Mets were able to face Papelbon in a tie game only because Bobby Parnell and Tim Byrdak escaped hairy jams in the seventh and eighth innings. But the latter Houdini act came at a cost; Thole suffered a possible concussion while tagging Ty Wigginton out at the plate in the eighth, and could be joining Tejada on the DL.
The Phillies had taken an early lead on John Mayberry Jr.'s sacrifice fly in the first inning, extending it on Placido Polanco's double off Niese in the second. Niese called those runs "devastating" considering the caliber of his competition: Halladay, perennially one of the best starting pitchers in the game.
But the Mets found a way to crack their nemesis Monday, when David Wright smoked a two-run double in the sixth. The game reset at that point, forcing both teams to dip liberally into their bullpens and benches.
At the end of theirs, the Mets found Valdespin.
A scout's dream because of his pure athleticism, Valdespin forced his way onto the prospect landscape last season by hitting 17 homers and stealing 37 bases over the top two levels of the Minor Leagues. With those numbers came talk of immaturity both on the field and off, though Valdespin nearly managed to make the big league club out of Spring Training.
Now he is here out of necessity. After playing the outfield for much of April at Triple-A Buffalo, Valdespin sat at his locker Monday afternoon and browsed a website advertising infielder's gloves. He is a natural shortstop, but has been playing that position less and less in recent years in an attempt to increase his versatility.
If he can hit, the Mets will find a place for him -- especially with Tejada injured. And Valdespin certainly hit Monday, becoming the first Mets player to launch a pinch-hit home run for his first Major League hit since Mike Jacobs in 2005.
"With the injuries that we've had," Wright said, referring to Tejada and Thole specifically, "for guys to come in and fill those voids and fill those roles and do some damage the way that they did ... that's huge for us."
Perhaps not surprisingly, Valdespin will be in the starting lineup Tuesday. Opportunity awaits.
"He is an extremely talented young player," manager Terry Collins said. "He's just so athletic. I know that he'll handle himself great. If he plays the way he's been playing since he's been here, and the way he's handled himself, he's got a chance to be here for a while."