Schilling pitched 20 years in the big leagues for the Orioles, Astros, Phillies, D-backs and Red Sox, posting 216 career wins with a 3.46 ERA. He was a six-time All-Star and finished second in Cy Young Award voting three times.
The 47-year-old also was 11-2 with a 2.33 ERA in 19 postseason starts.
Schilling has dealt with other health issues in the past, telling The Boston Globe he had a heart attack in November 2011 and had surgery to place a stent in one of his arteries. Schilling also told the paper he experienced chest pains while watching his wife, Shonda, run in the New York City Marathon.
"Shonda and I want to send a sincere thank you and our appreciation to those who have called and sent prayers, and we ask that if you are so inclined, to keep the Schilling family in your prayers," Schilling said.
"My father left me with a saying that I've carried my entire life and tried to pass on to our kids: 'Tough times don't last, tough people do.' Over the years in Boston, the kids at the Dana-Farber Cancer Institute have shown us what that means. With my incredibly talented medical team, I'm ready to try and win another big game.
"I've been so very blessed and I feel grateful for what God has allowed my family to have and experience, and I'll embrace this fight just like the rest of them, with resolute faith and head on."
Now an analyst with ESPN, Schilling agreed on a multiyear contract extension with the network in December. ESPN has not announced Schilling's broadcast plans for the 2014 season.
Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.