Zambrano moved to the setup role on April 22 after going 1-2 with a 7.45 ERA in four starts. The team needed a right-handed setup pitcher to bridge the gap to closer Carlos Marmol and also had to make room in the rotation at that time for Ted Lilly, who was activated from the disabled list.
But now, after eight relief appearances and a 6.23 ERA, Big Z will be used in long relief until he's built up enough stamina and arm strength to return to starting.
"'Z' gave it a good shot," Cubs general manager Jim Hendry said. "I think when he went to the 'pen with the one-inning-type potential, I think we all thought that when somebody goes from starter to the 'pen, they pick up juice and you get the one inning, let's go blow-it-by-people [approach]. We thought he was the right candidate for it."
But Zambrano's velocity didn't pick up, and in his last couple of relief outings, he's had trouble warming up quickly. His last short outing was on Friday against the Pittsburgh Pirates, and he gave up three runs on four hits in one inning and took the loss.
"It's no secret that for the last year, year and a half, he's not throwing as hard," Hendry said. "We thought [moving to the bullpen] might -- short term -- pick up his velocity, too."
When Piniella first announced that Zambrano was making the switch, it was stressed that the move was short term.
"It was something we thought would help the club at the time and help 'Z,'" Hendry said. "We wanted to see that consistent 'Z' who was pretty much dominant."
To get Zambrano ready, he will be used in long relief and could pitch a simulated game on Monday, which is an off-day for the Cubs. He met with pitching coach Larry Rothschild and Piniella on Monday and started his comeback program at that time, which is why he wasn't available in relief for that game. However, if needed, Zambrano could pitch on Tuesday.
"I said [moving Zambrano to the 'pen] wasn't going to be permanent when we did it," Piniella said. "Let's see how long he needs. We'd like to get him two or three appearances out of the bullpen stretched out."
There's no guarantees that Zambrano's velocity will increase if he's starting again.
"He didn't pitch poorly [in relief]," Piniella said. "But we haven't seen the increased velocity and that's the reason for this. When he's started games before its takes him two or three innings for him to hit top velocity. We took a chance, he helped us initially. Basically, it's allowed us to bring a few of these young kids along more. He helped us win some games."
Both Piniella and Hendry stressed that Zambrano is healthy, so that's not the reason for the slight drop in his velocity. The right-hander is coming off a disappointing season in which he went 9-7 and was unable to reach 200 innings. Zambrano was on the DL twice last season, but that was because of a hamstring injury and back problems.
"He's a horse. He's been a horse for a long time," Hendry said. "You don't throw 97 [mph] all your life unless your name is Mr. [Nolan] Ryan."
The Cubs are optimistic that switching Zambrano back to the rotation will revive him. But no one can say when.
"To make a specific plan or time frame is not right to the guys in the rotation now," Hendry said. "We're not five games under .500 because we've had a bad rotation. That's why I wouldn't quantify a date.
"We'll get him some more work, get him multiple innings. I think in the last couple weeks, he gave it a good shot. I applaud him that he came into camp in shape. He didn't do anything wrong. [Going to the bullpen] wasn't punishment. We didn't do this lightly. It was a well thought-out [plan], and at the time, it was the right decision.
"It didn't work perfectly how we planned it, so we'll adjust and get him ready for a different role."