In an exchange of first basemen, the Braves sent LaRoche to the Boston Red Sox for Kotchman and cash before Fridays 4 p.m. deadline to make trades without waivers.
LaRoche, who played in Atlanta from 2004-06, was traded for the second time this month. He was dealt from Pittsburgh to Boston on July 22.
Kotchman was traded almost exactly one year after he was acquired by the Braves from the Los Angeles Angels for Mark Teixiera.
Kotchman is hitting .282 with six homers and 41 RBIs and hasnt committed an error with the Braves.
LaRoche is batting .248 with 13 homers and 43 RBIs for Pittsburgh and Boston.