And the best part of the decision, Dempster said, is how Zambrano handled it.
"[Zambrano] said he was happy for me and said I deserved it," Dempster said. "That's somebody I look up to, who goes out and competes as hard as anybody I've been around. It meant a lot to hear something like that from him. It's a pretty respectful thing to say. It takes somebody big to say that, too, especially after you've started so many Opening Days in a row."
Manager Mike Quade made the announcement Monday after meeting with Dempster, Zambrano and Matt Garza in his office at Fitch Park. Garza will follow the two, getting his first start April 3 during the Cubs' opening series against the Pirates at Wrigley Field.
This will be Dempster's third career Opening Day assignment. His previous two were with the Marlins in 2001 and '02, and he did not get a decision in either.
Dempster, 33, went 15-12 in 34 starts last season, totaling 200-plus innings for the third consecutive year. Zambrano, 29, finished a dysfunctional season in which he was a starter, a reliever, on the restricted list and somehow finished 8-0 record in his final 11 starts.
"You think about Z's finish and Demp battling all year long and doing a good job," Quade said. "If there was something I lost sleep over, it was the two guys who have been with us and who gets the shot. I think I just thought we'd change it up a little. Z has done it. Let's see how it plays."
Part of Quade's decision was determined by the Cubs' April schedule. By having Zambrano pitch second in the order, he'll be in line to pitch in Milwaukee for the Cubs' first series against the Brewers from April 8-10. Zambrano is 9-5 with a 3.19 ERA in 16 career starts at Miller Park, and those numbers include his no-hitter against the Astros in 2008.
Quade considered talking to each pitcher individually, but instead called the three into his office at the same time.
"It would've been so easy to talk to each of us as individuals, but isn't that what we're trying to get away from?" Dempster said. "I think we're trying to be a team and unite as much as possible. I know Z was really happy for me. He told me so himself. That probably meant just as much as Quade telling me."
The fourth and fifth starters will be determined this spring. Garza, acquired from the Rays this offseason, was just happy to be included.
"I really don't care," Garza said. "I told [Quade] that. As long as he doesn't say, 'You're No. 6 or 7,' it doesn't bother me. At the end of the year, it won't matter. As long as we're playing in October, I don't care where I throw."
By holding Garza until the third game, the right-hander will have a chance to watch a couple games at Wrigley Field to get used to his new surroundings and scout the Pirates. It isn't that Garza can't handle Wrigley; he's pitched at Yankee Stadium and Fenway Park as a visiting player for a few years.
"He's confident, he's a competitor," Quade said. "He's OK with that, as far as going into that environment. I always harken back to my first time there as a coach. Your foundation is good and you feel good about it, but, man, oh man, I walked on that field and ... whew. It took a few days."
Garza said all he needs to know is what day he's throwing, and he'll be ready.
"I honestly felt I didn't even deserve to be up there with those two guys," he said. "They both have 10-plus years and I'm still trying to get my fourth one. Out of total respect, I think it's the way it should be set."
Dempster joked that Quade could've put the three names in a hat and pulled one out for the assignment, but there was more to the decision than that. Quade needed to give pitching coach Mark Riggins his pick to get the Cactus League rotation in line, so Quade slept on the decision Sunday night. When the Cubs' spring games begin Sunday, Zambrano and Garza will both pitch against the A's.
"They're all going to need to pitch well," Quade said. "It's Opening Day, and a big deal, but I looked at matchups going into Milwaukee, and so on and so forth. Riggs needs to know by [Tuesday], so what am I waiting for?"
Zambrano is 1-2 with an 8.26 ERA in his six Opening Day starts with the Cubs, and the team has won three of those games. Picking Dempster gives Quade a fresh start.
"There's some instinct here for me," Quade said. "I do pay attention to numbers, but you weigh it out and keep looking and it's him, him, him, and finally I said, 'This is the way we're going.'
"I don't think there was a bad decision here. I'm sitting here now, so this is what I came up with."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.