TUCSON _ Ubaldo Jimenez was expecting to get the Opening Day assignment for the Rockies, which he did Wednesday. The surprise came when Aaron Cook was in Jim Tracy‘s office when the manager told Jimenez he would oppose the Brewers on April 5 in Milwaukee.

Tracy said Cook, who started on Opening Day in 2007 and 2009, asked about 12 days ago if he could be there to congratulate Jimenez when Tracy informed him of the honor. Or as Tracy put it, Cook “very unselfishly is handing the torch to him.”

Jimenez, 26, has pitched in 84 games in the majors, including 83 starts. Cook, 31, has made 166 starts and has pitched in 197 games in the big leagues. When he made his debut in the majors in 2002, Jimenez was pitching in the Dominican Summer League. Cook is a consummate teammate and that he asked to be present when Jimenez received his good news, touched Jimenez.

“I have a lot of respect for him,” Jimenez said, “but right now I even more respect for what he did, that he came in with us. After Tracy told us, we walked outside (the office) and he gave me a lot of advice about opening day. He told me to just take it as another game and be prepared for it and just enjoy it.”

This will be the first Opening Day start for Jimenez, who is 1-0 at Miller Park where he has pitched seven scoreless innings. He went ent 15-12l;ast year with a 3.47 ERA, the lowest in franchise history for a starting pitcher, while logging 218 innings. Jimenez allowed 183 hits with 85 walks and 198 strikeouts and pitched at least six innings in a franchise-record 25 consecutive starts from May 1-Sept. 7.

As the No. 1 starter, Jimenez will have his share of confrontations this season with Tim Lincecum, Dan Haren, Clayton Kershaw and other No. 1 starters.

“I like challenges,” Jimenez said. “I’ll be there.”

Jimenez made his major league debut Sept. 26, 2007, and came back to the Rockies to stay in July 2007. He’s 31-28 lifetime with a 3.80 ERA and seems poised to take the next step and become a bona fide ace. A milepost along the way is getting to start for the first time Opening Day, an honor Jimenez will soon have on his big league resume, much to the joy of his teammates.

“It’s fantastic,” Jeff Francis said. “I’ve been here, since he first came on the team. The improvements he’s made have been phenomenal and he’s much deserving of that, that’s for sure.”