About a half hour later, Santana stepped down from the mound, whooping to his teammates as he descended the dugout steps. Santana would speak later about the importance of still feeling strong two days from now, five days from now, a month from now -- all crucial milestones in his road back from left shoulder surgery. But the gravity of this one afternoon was not lost on anyone.
"God almighty, I don't know if we can have a bigger step forward today than that," manager Terry Collins said.
From a statistical or even an anecdotal perspective, Santana did nothing spectacular on Tuesday. He pitched two innings. He allowed one hit and one walk. He threw 17 of his 29 pitches for strikes.
But it was the context of the day that tickled the Mets. For more than a year, Santana's coaches and teammates have been waiting patiently to watch him in person, in uniform, facing Major League batters on a Major League mound. The Mets kept close watch over his bullpen sessions and Minor League rehab assignments, knowing how critical his successes were to the franchise.
So when Santana did finally pitch Tuesday against a Cardinals lineup featuring more than a few regulars, the Mets did not dismiss it as mere Spring Training bluster. They embraced it.
"We take enough body blows as it is," Collins said. "We need to be able to put a smile on our face and say, 'Gosh darn, that's a good day.'"
If any one aspect of Tuesday's outing stood out to the Mets, it was that the stadium radar gun clocked Santana's fastball velocity at around 87-88 mph, recording one pitch as high as 90. Even Santana, who is typically firm in dismissing all talk of velocity, admitted that he glanced at the scoreboard "a couple times."
"But I wasn't focused on that," Santana said. "The most important thing today was that I felt good."
Mostly, Santana threw fastballs, mixing in a few changeups and sliders as he began finding his command -- including one particularly nasty change that Yadier Molina swung through. After walking the first batter he faced on the afternoon, Santana used his athleticism to turn a snappy double play on Skip Schumaker, then retired Matt Holliday, David Freese and Yadier Molina -- all productive Major League regulars -- on a flyout and two groundouts.
A single to Mark Hamilton spoiled what would have been a breezy second inning, but Santana induced another groundout from Matt Carpenter to complete his afternoon.
"He looked to me like he still has the good changeup," Cardinals manager Mike Matheny said. "It's a nasty changeup. You have to have some type of velocity to make that changeup work, and he looked pretty good."
From his vantage point on the bullpen mound, warming for his own appearance later in the game, R.A. Dickey continually snuck peeks to see how Santana was faring. What struck him most was the consistency of Santana's mechanics.
"To say that we're surprised would be an overstatement," Dickey said. "We're certainly encouraged and hopeful that he's going to be able to bring what he brought today."
To be clear, the Mets are still proceeding with extreme caution. Santana will throw a routine bullpen session later this week, in advance of his second Grapefruit League start on Sunday. And he will advance that pattern each week until his scheduled start on Opening Day.
It is all part of a carefully constructed plan to ease Santana back to the big leagues, following left shoulder surgery in September 2010 and a disappointing season of rehab in '11. At any point in that process, Santana could easily endure a setback, a bit of arm stiffness, some tightness -- anything. The Mets know that because they have seen it already, backing Santana off from his throwing program multiple times last season.
But Tuesday, for the first time in a long time, the Mets allowed themselves to forget about all that. They watched Santana no differently than the 4,537 fans in attendance did, overemphasizing his successes and ignoring his mistakes.
Given how cautiously they have watched his every move throughout the past 18 months, the Mets figured they deserved a day to revel.
"To sit here every day and say, 'Now we'll wait for tomorrow; we'll see how it is tomorrow' -- you've got to enjoy it for once," Collins said. "Enjoy a good day."