Dempster, sidelined since June 16 with a sore right lat, threw off the mound for the first time since June 15, when he threw seven shutout innings against the Red Sox, his last start.
"Everything went great today," Cubs manager Dale Sveum said Monday. "The bullpen was probably better than expected. We're just playing it by ear and see how he feels tomorrow."
Dempster joked he might be ready for the weekend series against the Mets. The Cubs' first post-break series against the D-backs is more realistic.
"We'll just see how I feel [Tuesday] and go from there," Dempster said. "[I'm] just stretching it out and stepping on the gas a little more each time and seeing where we get."
Neither Sveum nor Dempster felt the right-handed needed to make a rehab start in the Minor Leagues.
"The kind of guy he is and how he knows his body and the command of his pitches, I think as long as the bullpen goes good and we have a simulated game, that'll be enough," Sveum said.
Dempster has not given up a run in his last 22 innings over three starts, and was 3-3 with a 2.11 ERA in 12 starts before the injury.
"Obviously, going out there and not giving up runs every time is unrealistic," Dempster said. "At the same time, I feel really good about executing my pitches. For as bad as I felt, I feel really good now."