The right-hander, who has been on the 15-day disabled list since June 16, will pitch for Double-A Springfield on Thursday and Saturday, manager Tony La Russa said.
"If he was feeling great and we wanted to bring him up Saturday [it's a possibility], but I think the chances of that are slim," La Russa said on Tuesday.
Sanchez is 2-1 with a 1.88 ERA in 28 2/3 innings over 25 appearances this season. He's converted five of his seven save chances, fanning 33 against 16 walks.
The Cardinals are looking for depth in their bullpen after releasing Miguel Batista and Ryan Franklin in the past two weeks and placing Brian Tallet on the 15-day DL on Tuesday.