Marshall had his latest bullpen session on Tuesday, when coaches stood in at the plate to simulate batters.
"It went well. I struck all of the coaches out," Marshall joked.
Marshall threw 42 pitches, and said he was using maximum effort.
"It went great," Marshall said. "I used all of my pitches -- backdoor sliders, curveballs -- mixing pitches like it would be in a game. I'm not sore today."
Marshall, who went on the DL for the second time on May 24, has been throwing off of a mound for nearly two weeks. But there have been no plans made yet for a rehab assignment.
"I feel like I could definitely get some hitters out right now," said Marshall, who will throw another bullpen session either Thursday or Friday in Atlanta. "I think it's just a matter of making sure I'm completely ready and not rushing back. The bullpen has done an excellent job lately."