The Cubs' relief corps includes rookies James Russell and Justin Berg as well as Jeff Samardzija, Sean Marshall and Jeff Gray. Entering the season, Russell had appeared in no big league games; Berg, 11 games; Samardzija, 46; Marshall, 134; and Gray, 29.
"We have a wonderful young closer [in Carlos Marmol], and it's our job to get to him," Piniella said. "This will help us, and I think it'll help everybody else relax in the bullpen, including our setup guy.
"When we left Spring Training, we knew we had a lot of young kids, and we talked about how they would respond," Piniella said. "Right now, the bullpen is an area we need to fortify, and that's what we're doing."
The Cubs have been tweaking the bullpen since March when Angel Guzman was sidelined with right shoulder problems, which required arthroscopic surgery. Rookie Esmailin Caridad was to be the primary right-handed setup pitcher, but he's on the disabled list with a strained right forearm. He also was inconsistent, giving up four runs on three hits and three walks in 2 2/3 innings in four games.
The Zambrano move is temporary, Piniella said. Someone in the rotation was going to be bumped to make room for lefty Ted Lilly's return Saturday from the disabled list. The veteran has been rehabbing from arthroscopic surgery on his left shoulder. The 'pen needed an experienced, durable arm.
"I think it's a move that needs to be made," Piniella said. "A vast majority of these games are decided in the seventh and eighth innings. It's tough to bounce back from tough, tough losses late in the game. The least amount [of blown games] that you have, it buoys the confidence of the team and gets them on a little roll. All I'm saying is that's an area that needs some attention."
Grabow, 31, is the prime left-handed setup option and is tied with Marshall for a team-high eight appearances. He's been struggling as well, compiling a 0-2 record and 9.53 ERA.
"We're all just looking to get on a roll right now," Grabow said.
"I understand the situation," Zambrano said. "I understand we need a little help in the bullpen. We already lost three or four games in the eighth inning in relief. I'm not saying I will be a Superman, I'm not saying I'll be the best setup man in the business, but at least I will go and give the best I have to be the best.
"I think I can be good. I think I can be great," he said. "It's up to me."
Can he be as good as Marmol was in the setup role? Marmol shares the franchise record for most holds.
"I'll try to be the same or open the way for him to get a save," Zambrano said.
"It gives us some power at the end of the ballgame with Zambrano and Marmol," Piniella said. "That's some firepower."