The Washington Nationals placed All-Star left-hander MacKenzie Gore on the 15-day injured list Saturday with inflammation in his pitching shoulder.

Right-hander Mason Thompson was recalled from Triple-A Rochester to take the roster spot of Gore, who has struggled mightily since pitching in the All-Star Game last month. Gore is 1-5 in his last eight outings to fall to 5-13 with a 4.15 ERA on the season.

Gore, 26, is 26-39 with a 4.19 ERA in 102 career appearances (99 starts) with the Nationals and the San Diego Padres. He was selected by the Padres with the third overall pick of the 2017 MLB Draft before being traded as part of the blockbuster Juan Soto deal on Aug. 2, 2022.

Thompson, 27, struggled in his first stint with the Nationals this season, posting a 13.50 ERA over six relief appearances in July.

He is 0-1 with a 5.59 ERA in 10 relief appearances this season with Rochester.