Major League Baseball said the postponement was to allow for more testing and contact tracing.
New York was among the first major league teams to reach the 85% vaccination threshold to lessen coronavirus protocols such as dropping mask use in dugouts and bullpens.
The Yankees placed left-handers Nestor Cortes and Wandy Peralta on the COVID-19 injured list Thursday around midday.
New York players were on the field taking early batting practice about 3 1/2 hours before the scheduled start when the Yankees asked media to leave the field while the team conducted COVID testing.
Boston came onto the field as the postponment was announced to take batting practice.
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