McLouth went down with a strained muscle on his left side, and the Braves recalled former starter Jordan Schafer from Triple-A Gwinnett.
McLouth was hurt Sunday against the Los Angeles Angels when he checked his swing on a 1-2 pitch leading off the game. The same day, the Braves placed right fielder Jason Heyward on the DL with lingering stiffness in his troubled right shoulder. Wilkin Ramirez was called up from Gwinnett to take Heyward's place.
"Teams that can survive the injury bug are going to be there at the end, and we're going through that right now a little bit," manager Fredi Gonzalez said after Sunday's game. "But I think this team, mentally, is going to survive that."
The Braves also must contend with an ailing Tim Hudson, who returned to Atlanta to have his back examined after giving up eight runs over 3 2-3 innings and hitting three batters with pitches in a 9-0 loss to the Angels. The right-hander will miss Wednesday's scheduled start in Pittsburgh, forcing the Braves to make another roster move.
Left-hander Mike Minor will be called up from Triple-A to make the start.
The 24-year-old Schafer returns to the big leagues for the first time since 2009, when he was one of Atlanta's top prospects and claimed the starting center field job in spring training. He homered in his first career at-bat but was shipped to the minors after two months, batting .204 with a staggering 63 strikeouts in 167 at-bats.
The Braves were off Monday. They have lost four of five heading into a two-game series at Pittsburgh, which starts Tuesday.