The announcement was made by Executive Vice President/General Manager Ben Cherington.
Morales, 26, has gone 3-4 with one save and a 3.77 ERA (32 ER/76.1 IP) in 37 appearances this season, his first full campaign with the Red Sox. He has fanned 76 batters for an average of 8.96 strikeouts per 9.0 innings, the third-best mark this year among American League lefties with at least 65.0 innings pitched. In nine starts, all since June 17, Morales is 3-3 with a 4.14 ERA (21 ER/45.2 IP) and 47 strikeouts. His .204 opponent batting average (45-for-221) in 17 appearances since the start of June is the second-lowest mark in the Majors in that stretch (min. 50.0 IP). Originally signed by the Rockies as an international free agent in 2002, Morales has appeared in 175 Major League games (24 starts) over parts of six seasons with Colorado (2007-11) and Boston (2011-12), going 11-16 with 11 saves and a 4.36 ERA (124 ER/256.0 IP).
Aceves, 29, had been suspended for three games on Saturday for conduct detrimental to the team. The right-hander is 2-8 with 25 saves, a 4.60 ERA (32 ER/62.2 IP) and 57 strikeouts in 58 appearances this season, all out of the bullpen. He has a 26-11 record with 29 saves, a 3.27 ERA (110 ER/302.2 IP) and 224 strikeouts over 172 career Major League appearances (9 starts) with the Yankees (2008-10) and Red Sox (2011-12).