He laughed and joked in Spanish, as he usually does during these sessions. At one point, without perceptively changing his delivery, Santana sent a circle change tumbling toward the plate, floating an extra moment before smacking into the center of catcher Josh Thole's mitt. Manager Terry Collins, who had wandered over to the throng of onlookers, turned his head.
"That's filthy," Collins said. "You see that changeup? That's what he used to do."
What Santana used to do was lay waste to the highest level of professional baseball, ranking behind only Pedro Martinez for the league's lowest ERA (3.10) since 1979. What Santana has done recently -- for the past year, really -- is no different than what he did Tuesday: throw off a mound, sometimes off flat ground, tantalizing the Mets with shadows of his capabilities.
Collins said on Tuesday that Santana should be ready for Opening Day, following a run of bullpen sessions and five Grapefruit League starts. The Mets believe that he can make at least 25 starts this year; Santana offered an estimate as high as 30.
It all sounds good now, in Spring Training, on pitching mounds next to palm trees. But the overriding question is whether Santana, coming off a rare surgery and multiple setbacks, will be able to do it.
"In my mind right now, in my heart, he'll be ready," Collins said. "I don't think there's any question. He's gearing himself up for that, to be ready."
Those words are similar to the ones Collins spoke one year ago, when the Mets expected Santana back by late June or early July. Despite beginning a Minor League rehab assignment only slightly behind schedule, Santana never met that goal, pausing his throwing altogether following a midsummer setback.
He finally began a second Minor League rehab stint in September, before shutting down for the year in early October. By that point, Santana was 13 months removed from surgery and had been throwing baseballs regularly for nine of them. He was tired.
Now he is not.
"Going through everything I went through last year -- one day you feel good, another day you don't feel so good," Santana said. "It was like a roller coaster. Right now, so far, I'm feeling good."
By nature, shoulder injuries are more troublesome than elbow injuries, which disrupt pitchers but rarely dismantle careers. Anterior capsule tears, such as the one Santana endured in 2010, rank among the most vexing shoulder injuries of all.
Precious little data exists on such operations because only three prominent Major League pitchers -- Santana, Mark Prior and Chien-Ming Wang -- have undergone one in recent years. Prior's anterior capsule surgery effectively ended his big league career, though his was just the latest in a long line of major operations. Wang's knocked him out for two full years, with questions still lingering as to his long-term health.
Then there is Santana, now 17 months removed from his own anterior capsule procedure. Even today, he is unsure of his maximum velocity. He is unsure -- though cautiously optimistic -- about how his arm will respond from day to day, and whether he will regain the form that once made him a four-time All-Star and two-time Cy Young Award winner.
The only certainty at the start of camp is how the Mets still view him.
"He's the bull of the team," Thole said. "He's it."
That "it" factor is why dozens congregated Tuesday to watch Santana throw 30 pitches in a routine bullpen session. It is why an even larger crowd will gather when he throws a live batting-practice session later this month, larger still when he appears in his first spring game on March 5. It is why, when Collins says he expects Santana ready for Opening Day, people grin.
The Mets see Santana as indispensible for more than just his arm. His manager recalls an encounter with the left-hander in the spring of 2010, when Collins was still the organization's Minor League field coordinator and Santana was its reigning ace. Running an errand on the Major League side of Mets camp, Collins watched Santana personally halt his teammates during the middle of a routine fielding drill, scolding them for simply going through the motions.
"You don't think that speaks volumes?" Collins said, reflecting back on that day. "That's what he's going to bring to us."