Hall of Fame right-hander Bob Gibson, who won the Cy Young and National League MVP awards in 1968, sent a letter to living Hall of Famers informing them he is battling pancreatic cancer.

Gibson, widely considered one of the greatest pitchers of all time, was diagnosed with cancer several weeks ago, his longtime agent, Dick Zitzmann, told the St. Louis Post-Dispatch.

Zitzmann told the newspaper that he has spoken to Gibson and that chemotherapy is expected to begin Monday in Omaha, Nebraska, the pitcher's hometown. Gibson, who turns 84 in November, has been hospitalized in Omaha for the past two weeks.

"We all know what a competitor he is," Zitzmann told the Post-Dispatch.

Gibson went 22-9 and led the majors in ERA (1.12), shutouts (13) and strikeouts (268) in 1968 for the St. Louis Cardinals. The year before, he went the distance in three games, all wins, and St. Louis beat the Boston Red Sox in seven games in an epic World Series.

In 1969, Major League Baseball lowered the pitcher's mound from 15 inches to 10 inches in hopes of boosting offense. Gibson remained dominant, winning 20 games for the fourth time and completing 28 games in 33 decisions.

Gibson, who spent his entire career with the Cardinals, won 251 games over 17 seasons. He was inducted into the Hall of Fame in 1981.

The Cardinals offered their well wishes Saturday night, tweeting: "Get well soon, Bob. All of Cardinal Nation is behind you!"