"I feel like I'm making good progress," he said.
It was the third consecutive day that the right-hander was able to throw on flat ground. Augenstein said he threw from as far back as 175 feet, which was another step forward.
"It's getting the form back," he said. "It's testing it. I still felt a few things, but it's probably loosening back up and trying to get the flexibility back after all the strengthening I've been doing. It feels good, though."
Augenstein, who was 0-1 with a 9.53 ERA in five appearances before getting hurt, said there is no timetable for his return, but expects to go on a rehab assignment when he's healthy enough.
It could be difficult for the 6-foot-6 righty, who last pitched in the Major Leagues with the D-backs in 2009, to get a spot in the Cardinals' bullpen when he's recovered.
When Augenstein and lefty Brian Tallet (broken right hand) both went to the 15-day disabled list on April 13, the Cardinals recalled right-handers Fernando Salas and Eduardo Sanchez from Triple-A Memphis. Salas and Sanchez have impressed in late-inning situations, and Sanchez, the rookie from Venezuela, has converted two save opportunities.