Friday's game between the Boston Red Sox and Kansas City Royals at Fenway Park was postponed.
No makeup date has been announced.
The city of Boston is in lockdown as authorities search for the missing Boston Marathon bombing suspect.
Red Sox slugger David Ortiz was expected to make his season debut after starting the season on the disabled list because of an Achilles injury that limited him to 90 games last year.
Clay Buchholz (3-0, 0.41 ERA) was scheduled to match up with the Royals' James Shields (1-2, 3.43).
Boston (11-4) is riding a six-game winning streak while Kansas City (8-6) is coming off a two-game split against the Atlanta Braves.