Mulder said the session went fine and that he felt good following the workout. He will make another rehab start, most likely on Tuesday, for Triple-A Memphis.
"He's making progress," said pitching coach Dave Duncan. "He still has some things he needs to accomplish, but he's showing that all of the pitches he needs to pitch are in there now. He just needs to develop some consistency with those pitches."
Working out of the bullpen, Mulder threw 40-45 pitches. Both he and Duncan said velocity is not what they are focusing on, but rather the movement on Mulder's pitches.
Duncan said Mulder "is not the same guy" without an effective sinker -- a pitch he is very reliant on -- so it is more important to focus on that instead of how hard he can throw the baseball.
"I've never cared about velocity," Mulder said. "For some reason, people want to make a big deal about that. That has nothing to do with it. It's all about having your hand behind the ball and getting on top of it, and getting the downward plane that you need."
When he makes his next start, however, Mulder said he won't just assess himself on how well his pitches are moving. He said he will need to pitch better and more effectively off the mound, as well.
"I'm not going to sit there and watch all of the balls move," Mulder said. "The hitters will tell me that."
In two starts for Memphis, hitters have shelled Mulder. He lost both games he started and has a 13.03 ERA, while giving up 18 hits in 9 2/3 innings. If he does start on Tuesday, it will be against the Nashville Sounds at 6 p.m. CT.
Lee Hurwitz is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.