Astros outfielder George Springer left Sunday's game against the Red Sox in the fifth inning with stiffness in his lower back.
Springer was replaced in right field by Tony Kemp at the start of the bottom of the fifth inning. The Astros lost to the Red Sox 4-3 at Fenway Park.
Astros manager A.J. Hinch said Springer is day-to-day but definitely will not play on Monday when the Astros open a series against the White Sox at home.