NY Mets Legend Gary Carter -- Dead at 57

Hall of Fame catcher Gary Carter has died after a battle with brain cancer ... this according to his family.

The 57-year-old NY Mets legend had been diagnosed with an aggressive, fast-moving brain cancer last year.

Carter's daughter released a statement saying, "I am deeply saddened to tell you all that my precious dad went to be with Jesus today at 4:10 p.m."

She added, "This is the most difficult thing I have ever had to write in my entire life but I wanted you all to know."

Doctors had discovered 4 small tumors in Carter's brain ... after the MLB legend suddenly began to forget things, repeat questions and lacked energy.

Carter -- who was elected into the Baseball Hall of Fame in 2003 -- is survived by his wife, 3 children and 3 grandchildren.

Carter was one of the superstars on the world champion '86 Mets squad. He was also an 11-time All Star.