Former Montreal Expos catcher Gary Carter holds up a New York Mets and an Expos hat as Yogi Berra (R) looks on during opening ceremonies at Major League Baseball's All-Star game at Yankee Stadium in New York, in this file picture taken July 15, 2008. Hall of Fame catcher Gary Carter has been diagnosed with four "very small" brain tumors, the 11-times All-Star said in a statement issued by the New York Mets on May 21, 2011. [Photo/Agencies]

NEW YORK - Hall of Fame catcher Gary Carter said doctors discovered four "very small" brain tumors after he had an MRI scan on Friday in Florida.

The 57-year-old Carter said he expects to learn more about his diagnosis when he is examined again Thursday at Duke Medical Center.

"My wife, Sandy, and our children and family thank you for your thoughts and prayers," Carter said in a release issued Saturday by the New York Mets and baseball's Hall of Fame. "We ask that you please respect our privacy as we learn more about my medical condition."

The statement did not say whether the tumors are malignant or benign.

Friends and former teammates were stunned when they heard the news.

"The last time I saw him a couple months ago, he looked well. He was Gary," said Mets first base coach Mookie Wilson, a teammate of Carter's in the 1980s. "He seemed himself. No indication anything was wrong.

"Whatever the situation may be, of course I wish him well. And I hope things turn out for the best."

Lee Mazzilli, another teammate on the 1986 Mets, was on his way to Yankee Stadium when his wife called him with the news about Carter. He said he plans to reach out to Carter and his family when the time is right.

"You hope that it's not what you think it is," said Mazzilli, who works in corporate sales and sponsorships for the Yankees. "It breaks your heart. But I think if anyone has an optimistic outlook, he has one."

Carter hit .262 with 324 homers and 1,225 RBIs in 19 seasons in the majors. The 11-time All-Star played his last game with the Montreal Expos in 1992 and was inducted into the Hall of Fame in 2003.

The effervescent Carter, nicknamed "Kid", is perhaps best known for helping the Mets win the 1986 World Series. He had 24 homers and 105 RBIs that year, then drove in 11 runs in the postseason.

"On behalf of the Mets organization, our thoughts and prayers are with Gary, Sandy and the entire Carter family," said Jeff Wilpon, the club's chief operating officer.