NEW YORK -- Hall of Famer Lou Brock, who had part of his left leg amputated in 2015 due to complications from diabetes, is battling health issues again, the Cardinals announced on Thursday.
According to the organization, Brock is undergoing treatment for multiple myeloma, a blood cancer that starts in the bone marrow's plasma cells. As a result, Brock has had to cancel his scheduled appearance at the Budweiser Bash at Busch Stadium on April 25.
The diagnosis came recently, according to the Cardinals, and Brock is undergoing treatment in St. Louis, a city he made his home after playing parts of 16 seasons with the Cards.
"[My wife] Jackie and I appreciate the prayers and support we have received from our many friends and fans in the Cardinals community," Brock said in a statement. "We count ourselves blessed that I am receiving the best possible medical treatment, and we look forward to seeing many more Cardinals World Series Championships in the future."
The medical complications precluded Brock from being able to make an appearance at the Cards' Spring Training camp, where he usually serves as a guest instructor. He was missing from the team's Opening Day festivities as well.
Brock, 77, was elected into the National Baseball Hall of Fame in 1985 after a 19-year career in which he stole 938 bases -- still a National League record. He posted 12 seasons with 50 or more steals in a season, and he ranks 25th on the all-time list with 3,023 hits.
Brock was a member of two World Series championship teams and established Major League records for highest career Fall Classic batting average (.391) and the most stolen bases in a single World Series (seven in both 1967 and '68). His uniform number (20) is one of 12 that have been retired by the Cardinals.
Jenifer Langosch has covered the Cardinals for MLB.com since 2012, and previously covered the Pirates from 2007-11. Follow her on Twitter, like her Facebook page and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.