San Antonio Spurs rookie guard Dylan Harper has been ruled out of Game 2 of the Western Conference finals because of a right leg injury.

Harper was injured in the third quarter when he landed awkwardly on a layup attempt. He immediately grabbed at his leg in pain before checking out of the game moments later.

Earlier in the night, Spurs coach Mitch Johnson adjusted the rotation by inserting reserve point guard Jordan McLaughlin, which turned out to be a prescient move once McLaughlin was needed to step up to replace Harper. San Antonio has already struggled with ball security without injured star guard De’Aaron Fox, who has been the team’s offensive catalyst throughout the season. With Harper sidelined, the Thunder’s ball pressure becomes an even greater concern for the Spurs.

Before Wednesday’s game, Harper earned NBA All-Rookie First Team honors and had played a key role filling in for Fox, who has missed the first two games of the Western Conference finals.