Starting Sept. 1, rosters can be expanded to include players already on the 40-man roster. Infante had to be put on that 40-man list so right-hander Clevelan Santeliz was designated for assignment.
The White Sox are still expected to recall Dayan Viciedo and Carlos Torres once their minor-league season ends next week. Torres was sent down this week to make room on the major-league roster for Manny Ramirez.
Infante, a right-handed reliever, started the year at Single-A Winston-Salem before advancing to Double-A Birmingham. He was 3-4 with a 3.45 ERA, 12 saves and 69 strikeouts in a combined 55 games.
De Aza, an outfielder, batted .302 with 21 doubles, four triples and 49 RBIs in 79 games for Triple-A Charlotte. The 26-year-old played 67 major-league games with the Marlins in 2007 and 2009.
Flowers, a catcher who is considered one of the top prospects in the organization, batted just .220 in 100 games at Charlotte, with 16 home runs and 53 RBIs. He went 3 for 16 in 10 games with the White Sox in 2009.