Aumont, 22, posted a 2-5 record with seven saves in nine opportunities and a 2.68 ERA in 43 combined games for double-A Reading and triple-A Lehigh Valley in 2011. Between both clubs, the 6-foot-7 reliever recorded 78 strikeouts in 53.2 innings and held opponents to a .216 batting average. The Phillies Minor League Pitcher of the Week for April 7-17 of this year, Aumont was acquired via trade from the Mariners in 2009. He was a first-round selection (11th overall) of Seattle in the 2007 draft. Following the season, Aumont was named the fifth-best prospect in the Phillies minor league system by Baseball America.
Diekman spent the 2011 season with Reading where he went 0-1 with three saves and a 3.05 ERA in a staff-leading 53 appearances. After allowing 13 earned runs in 18.0 innings over his first 18 appearances, the 24-year-old Diekman posted a 1.72 ERA over his final 35 games of the season. He struck out 83 batters in 65.0 innings and held opponents to a .199 average which included a .099 mark against left-handed hitters. Following the season, Diekman, a 30th round selection by the Phillies in the 2007 draft, pitched for Scottsdale of the Arizona Fall League where he allowed just one earned run over 11.1 innings with 14 strikeouts.
Valle batted .284 with five home runs and 40 RBI in 91 games for single-A Clearwater last season. The 21-year-old had 27 multi-hit games on the season and batted .368 against left-handed pitching. Signed by the Phillies as an amateur free agent in 2006, Valle has played for Caneros de los Mochis in the Mexican Pacific League this fall. He was named the third-best prospect in the Phillies minor league system by Baseball America following the season.
Gillies, 23, appeared in only three regular season games for Clearwater in 2011 due to injuries. After the season, he played for Scottsdale in the Arizona Fall League. Gillies, acquired by the Phillies along with Aumont in a 2009 trade with Seattle, was a 25th round selection of the Mariners in the 2006 draft.
With the additions of Aumont, Diekman, Valle and Gillies, the Phillies now have 39 players on the 40-man roster.