San Diego shortstop Fernando Tatis Jr. sustained a partial dislocation of his left shoulder and exited the Padres' home game against the Colorado Rockies in the first inning.
Following the game, a 9-4 Rockies win, the Padres announced that Tatis is day-to-day.
With Tatis on first base after a single, Manny Machado hit a grounder that kicked away from Rockies third baseman Ryan McMahon. Tatis came around second and tried to advance to third, but he was retired when McMahon threw to shortstop Brendan Rodgers, who moved over to cover the bag.
Tatis went to the ground after he was tagged out, clutching his left arm.
He dealt with left shoulder separations several times earlier this year, and he missed nine games while on the injured list in April due to the same ailment.
Tatis, 22, was a first-time All-Star this year. Entering play Friday, he led the National League in homers (31), stolen bases (23), runs (78), slugging percentage (.650) and on-base-plus-slugging percentage (1.021).
--Field Level Media