NEW YORK -- As long as a wave of back discomfort does not stop him, Johan Santana will make his next start as scheduled, Thursday against the Rockies. There's a decent chance he will make another start after that, as well.

But in regards to Santana's future, nobody knows for certain. Santana and various Mets officials huddled after returning to New York on Sunday night and, with no dissenting voice in the group, decided to proceed Thursday on a strict pitch count of less than 100. Still, at some point in the near future, the Mets may revisit the idea of shutting him down for the season.

"At some point, there's a diminishing return," general manager Sandy Alderson said. "It's been a long year, a long offseason of rehab. Johan actually has accomplished quite a bit over the course of this season, and at the appropriate time, we really have to think as much about next year as we do about this year."

The latest ripple in that saga could force the Mets' hand. Some hours after Santana insisted upon his health, the left-hander assented to an MRI on his ailing back. He will undergo that test on Tuesday, with the results determining if he can start Thursday's game.

"He came in stiffer today than he had been," manager Terry Collins said. "The doctor thought they should take a look at it."

No one in the organization has completely dismissed the possibility of Santana finishing out the season in the rotation, which would result in at least seven more starts. But those involved in the decision process -- namely Santana, Alderson, Collins and pitching coach Dan Warthen -- indicated that the Mets are likely to shut down Santana before that point.

"We're in this together," Santana said. "It's not just what I'm thinking or what they're thinking. We have come a long way, and they know that. And I'm very happy with everything that I've been able to accomplish. Even though I've been struggling lately, that doesn't mean that you can't see positives around everything that I have done."

A confluence of factors has led to this juncture. With the Mets out of playoff contention, there is little reason to continue escalating Santana's innings total in his first season back from major shoulder surgery. There is reason to believe Santana could benefit from an extra month of offseason rest, given his 0-5 record and 15.63 ERA over his last five starts, as well as the presence of nagging ankle and back discomfort. There is also value in clearing rotation space for youngsters Jenrry Mejia or Jeurys Familia to make a few starts down the stretch.

But Collins indicated that there is also value in having Santana finish his season on a high note, as well as a practical reason for waiting: If Santana makes his next two starts as scheduled, that would take the Mets to Sept. 1, when they can expand their roster to replace him without playing short-handed.

"The rationale for shutting him down, if we do shut him down, will be that he's accomplished things that we wanted him to accomplish," Collins said. "We got innings that we wanted him to have. We got him to a point that we thought where there's nothing more to gain here and only things to lose. That would be the rationale if the time comes."

Santana began the season better than most anyone expected, going 3-2 with a 2.38 ERA over his first 11 starts while striking out 68 batters in 68 innings. But after throwing a career-high 134 pitches in his no-hitter on June 1 against the Cardinals, the left-hander began scuffling, ultimately landing on the disabled list with an ankle injury. He has not been the same since.

So there is a good chance the Mets shut Santana down in the hope that he can give them a full, healthy, dominant season in 2013. They just will not do so quite yet.

"I've been through a lot this year -- a lot," Santana said. "But I'm still here. To me, that means a lot, and I'm going to continue until they don't want me to."

Mets international signee Rosario takes BP at Citi

NEW YORK -- Among those taking their hacks during batting practice Monday at Citi Field was German Rosario, the 16-year-old Dominican shortstop the Mets signed to a record $1.75 million contract last month.

"I was kind of scared, kind of nervous," Rosario said through an interpreter. "But it's getting better."

Rosario, who named former Mets shortstop Jose Reyes as his favorite player, recently earned the highest bonus the Mets have ever given to an international player. A graduate of Centro Educativo Rosario High School in the Dominican, Rosario will report to the Mets' instructional camp this fall.

"It was good," the shortstop said of his first Citi Field experience, "but I need to keep working to get better."

Worth noting

The Mets placed Jeremy Hefner on paternity leave following Monday's 3-1 loss to the Rockies so he can join his wife, Sarah, for the birth of the couple's second child. Sarah Hefner is scheduled to have labor induced on Wednesday, and Hefner, who is slated to start Sunday for the Mets, will be back in uniform Friday. The Mets recalled left-hander Robert Carson from Triple-A Buffalo to replace Hefner on the roster.

• Merengue Night will return to Citi Field this Friday, following the Mets' 7:10 p.m. ET game against the Astros. Scheduled to perform in the postgame concert are Latin artists Sergio Vargas, Raymond & Miguel, Juliana and El Batallon. Tickets are available at mets.com or 718-507-TIXX.