The 36-year-old Boone was diagnosed with a congenital defect in his heart where the valve has two — not the normal three — cusps to manage blood flow. The surgery will be performed at Stanford University Medical Center on Thursday.

The Astros signed Boone in the offseason. He announced his condition at spring training on March 18 and said he's uncertain if he'll ever play baseball again.

Boone has played for Cincinnati, the New York Yankees, Cleveland, Florida and Washington in his 12-year major-league career.

Boone said at spring training that he felt fine, but a routine physical determined he needed surgery.