ATLANTA -- Starter Reynaldo Lopez was placed on the injured list after with left knee inflammation after he was scratched before Saturday's scheduled start against the Nationals, Braves manager Walt Weiss said.
The Braves announced that Lopez was unable to pitch 35 minutes before the game. The right-hander was injured during his warmup routine.
"I don't know how serious it is, but when you get scratched from the start, that's pretty much always going to be an IL," Weiss said after the Braves' 8-3 victory over the Nationals.
Right-hander JR Ritchie was recalled from Triple-A Gwinnett to start Sunday's game against the Nationals.
The loss of López adds more urgency to the Braves' expected search for rotation help before Monday's 6 p.m. ET trade deadline.
Lopez (4-3, 3.64 ERA) is coming off a strong start in Baltimore on July 26, when he threw 5⅔ scoreless innings in a game the Braves eventually won in 11 innings. Lopez started the season in the rotation, was moved to the bullpen and made 13 appearances, and returned to the rotation June 26, making six starts.
Martin Perez was scheduled to pitch for the Braves on Sunday, but he stepped up when Lopez went down and allowed just one hit and no runs in seven innings.
The Braves have won the first three games of the four-game series against the Nationals.
Ritchie is 1-2 with a 4.50 ERA in 13 games, including seven starts, with Atlanta.