Boston Red Sox right fielder Mookie Betts was scratched from Sunday's game against the Atlanta Braves with left side tightness.
The team said Betts is day-to-day.
Andrew Benintendi moved to leadoff and played center instead of left. Blake Swihart took Betts place in the lineup, playing left field and Jackie Bradley Jr. moved from center to right for Sunday's game.
Betts leads MLB with a .359 average and was tied in homers with Los Angeles Angels outfielder Mike Trout with 17. Betts is alos first in the majors in runs scored, slugging, and OPS.
Boston started the day two games ahead of the New York Yankees in the AL East.