BOSTON (AP) – Curt Schilling has an undisclosed injury in his right shoulder, and the pitcher has been squabbling with the Boston Red Sox over whether he should have surgery that could cost him the season or try something less drastic.

Writing on his blog, 38pitches.com, Schilling said Thursday night that he has agreed to abide by the club’s request to rely on rest and rehabilitation.

“There have been disagreements these past few weeks in an effort to provide me with a solution that would allow me to pitch as much as possible during the 2008 season,” Schilling wrote. “At no time did I ever consider taking a course of action against the club’s wishes. In the end, regardless of who agreed with whom, I have chosen the club’s course of action and will vigorously pursue any and every option I can to be able to help this team to another World Series title in 2008.”

Red Sox officials have declined to comment other than to issue a two-sentence statement Thursday night confirming that Schilling is injured.

“Curt Schilling was examined by Red Sox doctors in January after he reported feeling right shoulder discomfort,” the team said. “Curt has started a program of rest, rehabilitation and shoulder strengthening in an attempt to return to pitching.”

The Boston Herald first reported Schilling’s injury on its Web site, saying the injury was serious enough to consider surgery that could keep him out for the whole 2008 season. The Boston Globe reported later Thursday that even without surgery Schilling would be out until at least the All-Star break.

The dispute over Schilling’s treatment went far enough to lead Schilling to consult with the players’ union over his rights.

“I have been consulted by Curt and his representative,” said Michael Weiner, a lawyer for the players association. “The Red Sox have no basis to take any action against Curt.”

According to a side letter to the collective bargaining agreement, a player has the right to seek a second opinion from his own doctor, but it’s in dispute what happens when the team’s doctor and the player’s disagree on the treatment.

Schilling, who spent seven weeks on the disabled list with right shoulder tendinitis last year, went 9-8 with a 3.87 ERA during the regular season last year. In the playoffs, he went 3-0 with a 3.00 ERA to help the Red Sox win their second World Series in four seasons.

He agreed in November to a one-year, $8 million contract that allows him to earn an addition $5 million in performance and weight bonuses. The 41-year-old right-hander has said that this will be his last year.

Schilling said he passed all physical exams when he negotiated his new contract.

“I knew in my heart of hearts that the extra time I was giving my arm to rest this winter would in fact be the cure for what I went through the entire 2007 season,” he wrote. “I had a strong desire to not have to go through multiple cortisone injections in my shoulder for another year. There was absolutely no reason for anyone involved to believe I would be anything other than completely healthy and ready for the 2008 baseball season.

“Things have changed since then.”

The co-MVP of the 2001 World Series and a star in both of Boston’s recent titles, Schilling became a free agent after the ’07 Series but agreed to a deal that included $5 million in weight and performance incentives. The Red Sox questioned whether Schilling’s offseason conditioning last winter was responsible for his dropoff in the ’07 regular season.

The Red Sox had discussed – and dismissed – the idea of using a six-man rotation this year. With Schilling out for an extended period of time, they are expected to rely on Josh Beckett, Daisuke Matsuzaka, Jon Lester, Tim Wakefield and Clay Buchholz.