Domingo, the general director of the National Opera, will also sing "God Bless America" during the seventh-inning stretch. In the latter performance, he will be accompanied by musicians from the opera company's Domingo-Cafritz Young Artist Program.
The game, which begins at 1:05 p.m., will be broadcast live on Washington's WDCA television.
The tenor will also be seen next week playing in the National Opera's second annual golf tournament, on September 6 at River Creek Club in Leesburg, Virginia. The event, dubbed "The Domingo Cup," is a benefit for the company's training programs. Golfers wishing to participate should visit www.dc-opera.org.
According to a press release, Domingo is a "huge sports fan."