SAN FRANCISCO -- Rockies right-hander Alex White, who has shown quality stuff at times but has not pitched as many as five innings in any of his last nine starts, will move to the bullpen to make room for left-hander Jorge De La Rosa.

The Rockies will start De La Rosa -- out since May 2011 because of Tommy John left elbow surgery -- on Thursday against the Giants. Manager Jim Tracy said he hopes White uses the bullpen experience to jump-start himself on the road to efficiency. Tracy said the Rockies haven't given up on White (2-8, 5.15 ERA) as a starter.

"I don't want Alex White to sit and feel he's the guy that's being singled out -- we want to teach all the guys the importance of efficiency," Tracy said. "Hopefully, this will end up being a very worthwhile thing.

"In a perfect world, I want him to be one of our starters that become much more efficient, with the type of stuff that he has, the effectiveness that he has with his sinker and how good he can be."

De La Rosa slated for season debut Thursday

SAN FRANCISCO -- Jorge De La Rosa admits having Opening Day excitement in the dying days of the Rockies' season.

De La Rosa is scheduled to make his season debut for the Rockies in Thursday afternoon's finale of four games with the Giants. It will be his first Major League appearance since May 24, 2011, when he suffered a left elbow injury that required Tommy John surgery. Twice, De La Rosa had injury rehab assignments halted because of tightness and swelling in the elbow.

But De La Rosa was pain-free and mostly effective in three recent starts, one at Rookie-level Grand Junction and two at Class A Modesto. An excited De La Rosa, 31, said he'll just have to battle an old demon when he finally takes the mound.

Before finding his form with the Rockies -- he is 39-28 with a 4.38 ERA and the team is 50-35 in his starts -- he bounced through four Major League organizations and the Mexican League. A major issue was a lack of ability to control his emotions. There will be plenty of emotions Thursday.

"It's really exciting to be back in the game," De La Rosa said. "But at the same time I have to be calm, don't get too excited on the mound. That will be real hard for me, but I will try to stay calm and make my pitches."

Rockies manager Jim Tracy said De La Rosa built himself to 95 pitches during his rehab assignment, but he will be watched closely Thursday. He'll have two or three starts before season's end. De La Rosa and Tracy each said it's unclear if the Rockies believe the starts will be enough to give De La Rosa full confidence going into next year, or if the team will recommend he pitch in winter ball in his native Mexico.

Tracy is happy, even if it's for just a few games, to have a rotation that simultaneously includes De La Rosa, fellow veteran left-hander Jeff Francis and right-hander Jhoulys Chacin, who missed more than three months with a nerve issue in his chest. The Rockies were counting on De La Rosa and Chacin being together and effective earlier, and they signed Francis as a free agent in June.

De La Rosa had hoped to be back in May.

"I haven't seen him for 16 months, and I've missed him," Tracy said.

Rockies pleased with Pacheco's hitting approach

SAN FRANCISCO -- The Rockies' Jordan Pacheco entered Monday's game against the Giants leading National League rookies with a .301 batting average and looking to bring power in the future.

Pacheco has played most of the season at third base and first base (where he started Monday) and has four home runs. Those positions traditionally have hitters with greater power, but the Rockies like his approach and are not pressing him to swing for the fences.

"Everybody in our organization knows that he's got very good fundamentals with his swing and stance," Rockies hitting coach Carney Lansford said. "Very little movement means fewer things can go wrong. He does a good job. He knows what kind of hitter he is.

"He's a line-drive hitter. He can hit some doubles and the occasional home run. Down the line there will be a little more as far as power goes. There are adjustments he can make with his stance and swing, which he has done. He can get a little stronger with his legs, because that's where power comes from, the legs."

Pacheco said Lansford has encouraged him to keep his approach simple this season, and he hopes to advance in the future.

"We're all trying to get better," Pacheco said. "I'm trying to be the best player I can possibly be. I'm going to take chances. I'm going to try different things. If it works, it works. If it doesn't, it doesn't. But I know I have a base and everybody here has a base of what they can do well. It's good to be able to fall back on that when things aren't going well."

Worth noting

• Rockies All-Star left fielder Carlos Gonzalez was not in the starting lineup Monday because of cramping in his left hamstring, Tracy said. Gonzalez will be re-evaluated Tuesday.

• Rockies catcher Ramon Hernandez was scheduled to undergo surgery on his right hamstring Monday. He will miss the remainder of the season.