Zambrano, who has not started a game since April 20, most likely will pitch in the rotation this weekend during Chicago's series against the Astros.
The game with the Pirates will be made up Monday, which would fall on Ted Lilly's turn to start. But Cubs manager Lou Piniella doesn't want him to face the Pirates for the fourth time this season.
"I think we'll pitch [Zambrano] in Houston," Piniella said. "We'll try to juggle our rotation to see if we can pitch somebody different Monday."
"Our preference is to get Zambrano right back on the mound pitching," Piniella said. "I'll get together with the pitching coach on our flight and we'll figure this out."
Zambrano was sent to the bullpen April 24 to help with the team's late-inning relief problems. In 2010, he's a combined 1-3 with a 6.12 ERA.
The 29-year-old pitcher made four starts before moving to the bullpen. His last victory as a starter came April 10 against the Reds. In that contest, Zambrano pitched seven innings, giving up six hits, three earned runs, walked two and struck out nine.
Bruce Levine covers baseball for ESPN 1000 and ESPNChicago.com.