Wednesday's game was suspended in the top of the tenth inning after a rain delay of 109 minutes.
The game will be continued on Thursday, August 22, at 1 PM. Boston reliever Josh Taylor had thrown only three pitches in the inning, a 2-1 count on Meibrys Viloria.
August 22 is an off-day for both teams. The Red Sox host the Phillies on Wednesday, so they'll stay in Boston an extra day before flying to San Diego. The Royals' schedule has them in Baltimore on Wednesday and in Cleveland on Friday.
J.D. Martinez (2-for-5) hit a two-run homer in the fourth and Xander Bogaerts (3-for-5) doubled in two runs in the fifth.