PORT ST. LUCIE, Fla. -- Johan Santana's competitiveness got the best of him.
According to Mets manager Terry Collins, that's what drove Santana to throw an impromptu bullpen session Sunday morning, his way of silencing critics who questioned his readiness to pitch.
"It was unnecessary," said Collins, who spent about 10 minutes Monday telling Santana not to risk injury to his surgically repaired left shoulder simply to prove a point.
The Mets' plan called for Santana to long-toss Sunday morning. But after the planned session, Santana called an audible, throwing roughly 15 pitches off the mound for the first time in nearly two weeks.
"In retrospect, he knows he would have handled it a bit differently," said Collins, who pulled Santana aside a few hours before the Mets' 4-2 loss to the Braves. "But he's fine and he wanted to show everybody he was fine. I just said, 'Look, we're going to do this the right way, we're not going to hurt you, we're not going to get you injured. I don't care how upset you are about things, we're going to do this the proper way.' "
Santana, 33, had been shut down after his first two mound sessions set off alarm bells among team officials. They believed that Santana's shoulder fatigue stemmed directly from his decision to cut down on his typical offseason throwing program.
The Mets have not given up hope that Santana will be ready for his Opening Day assignment April 1 against the Padres. Despite recent progress in his throwing program, however, his chances of taking the ball for the opener appear increasingly slim. During his chat with Santana, Collins told him that staying healthy remains the top priority, not starting on Opening Day.
"I said the last thing I need is to have you wake up tomorrow stiff," Collins said. "We'd take a huge step backward just because you wanted to show everybody you're OK. I understood what you're doing, but once in a while, you've got to let stuff fly away. You've got to just let it roll off your back and move on. And he knew that."
Even Collins seemed caught off guard by Santana's decision to throw Sunday. The two had chatted earlier in the day, and Collins said Santana had not left the impression that he was upset. But by the end of the day, it was clear that something had changed.
Nevertheless, Santana emerged from the unplanned throwing session with no issues.
"He got pretty aggressive with his throwing yesterday," pitching coach Dan Warthen said. "And he felt absolutely great today."
Warthen said Santana continues to make "big progress" in trying to rebuild strength in his shoulder. He bounced back well from the throwing session, spending part of Monday morning long-tossing with reliever Pedro Feliciano.
The next step comes Wednesday, when Santana will long- toss and then throw a bullpen session, which this time is part of the plan. Warthen said Santana will work with more intensity than he did Sunday, though he will follow a similar routine. Santana will throw from a reduced distance, with the catcher setting up a few feet in front of the plate.
Santana, who is guaranteed $31 million this season, once again declined interview requests. But he offered a brief update about his morning throwing session.
"Good," he said as he moved through the clubhouse. "That's it, guys. Good."