CHICAGO — Hall of Fame second baseman Ryne Sandberg has been diagnosed with metastatic prostate cancer.

The 64-year-old Sandberg said Monday in a release put out by the Baseball Hall of Fame that he has started treatment.

“I am surrounded by my loving wife Margaret, our incredibly supportive family, the best medical care team, and our dear friends,” Sandberg said. “We will continue to be positive, strong, and fight to beat this. Please keep us in your thoughts and prayers during this difficult time for me and my family.”

Sandberg hit .285 with 282 homers, 1,061 RBIs and 344 steals in 16 seasons in the majors. He made his big league debut with Philadelphia in 1981 and appeared in 13 games with the Phillies before he was traded to the Chicago Cubs in January 1982.

Sandberg turned into one of the majors’ best all-around performers with the Cubs. He made 10 All-Star teams and won nine Gold Gloves. He also was the NL MVP in 1984.

He was inducted into Cooperstown in 2005.

“Part of what made Ryne a tremendous talent on the field was his quiet intensity, and we have no doubt he’ll bring the same tenacity to his fight,” Hall of Fame chair Jane Forbes Clark said in a statement.

“During this difficult time, we join Cubs fans in Chicago, and baseball fans everywhere, in sending love and support to Ryne and Margaret and the entire Sandberg family.”