"Now you can call it a setback.

Johan Santana won't make his next rehab start in Port St. Lucie tonight or tomorrow, as the Mets had hoped he would. Instead, the lefty will fly back to New York to see a doctor tomorrow at the Hospital for Special Surgery after experiencing "lingering discomfort" in his surgically repaired left shoulder, according to general manager Sandy Alderson.

Santana pitched three scoreless innings for Class-A St. Lucie on Thursday and said he complained of a lack of strength on Monday, but yesterday Alderson said Santana was feeling worse.

He now won't pitch again until Monday at the earliest, and Alderson admitted this was a setback after yesterday calling it a "tweak in the schedule."

"It was a day-by-day proposition to see how he came back from his original three innings," Alderson said. "I think he has less confidence than he might have, so it was prudent to have him checked out. And it will either be reassuring or we'll step back and see where we are."

Santana has been on a 30-day rehab stint, but that likely will be reset on Monday after he hasn't thrown for seven days.

The 32-year-old underwent the same procedure to fix a torn anterior capsule of his throwing shoulder as Chien-Ming Wang did, and Wang just returned to the Nationals after a two-year absence. Using that timeline, the Mets' hopes of having Santana pitch this year after undergoing the surgery in September was ambitious, but Alderson still won't rule it out."