SAN FRANCISCO -- Giants shortstop Edgar Renteria left Friday night's series opener against the Colorado Rockies after two innings with tightness in his groin.

Renteria, who is listed as day-to-day, missed two games last week with discomfort in his left shoulder.

Renteria drew a first-inning walk and slid into second base in an attempt to break up a double play, then stayed in the game for the second inning and handled a routine Clint Barmes grounder.

But when the Giants took the field for the third inning, Juan Uribe moved from second base to shortstop, Mark DeRosa switched from left field to second base and John Bowker entered the game to play left.

Molina moves back into cleanup spot

SAN FRANCISCO -- Meet the new cleanup hitter. Same as the old cleanup hitter.

Giants manager Bruce Bochy moved Bengie Molina to the No. 4 spot in the batting order on Friday, the berth that the catcher occupied for most of the previous two seasons.

Aubrey Huff, who entered the game in a 3-for-27 skid that shrank his batting average to .227, was dropped from cleanup, where he had hit in each of the 20 games he had started, to fifth. Mark DeRosa, hitting .222 overall and .182 (4-for-22) in the previous six games of this homestand, shrunk from fifth to sixth.

But Bochy said that he had contemplated this alignment intermittently since March and emphasized that dissatisfaction with Huff or DeRosa didn't prompt the switches.

"It was more wanting Bengie there [at cleanup] than a demotion [for Huff and DeRosa] or however somebody looks at it," Bochy said.

Statistics supported Bochy's case. Molina entered the series opener against the Colorado Rockies hitting .350, including .421 (8-for-19) on the homestand, though he had only one home run and eight RBIs. Before Friday, Molina had hit fifth four times, sixth 11 times and cleanup once -- in the lone game Huff didn't start.

Molina also owned a lifetime .333 average (6-for-18) against Aaron Cook, Colorado's starting pitcher on Friday.

Who will go when Rowand returns?

SAN FRANCISCO -- Having recovered sufficiently from three fractures around his left cheek and eye, center fielder Aaron Rowand likely will be activated from the 15-day disabled list on Sunday, the first day he's eligible to return.

The only intrigue involves the corresponding move the Giants must make to clear roster room for Rowand, who was injured on April 16, when he was beaned by a fastball from Dodgers right-hander Vicente Padilla.

Predictably, manager Bruce Bochy declined to discuss specifics on Friday.

"It may come down to a position player or a pitcher," said Bochy, who already has begun discussing the matter with general manager Brian Sabean. "We'll see where we're at and what our needs are."

Infielder Matt Downs, who was recalled from Triple-A Fresno when Rowand went on the DL, isn't an automatic selection for demotion. Downs has looked sharp in limited action, hitting .308 (4-for-13) with a home run and a double.

A member of the crowded outfield could be vulnerable, particularly Eugenio Velez or John Bowker, who have Minor League options remaining.

Sending down a reliever is a possibility. Not only has the starters' effectiveness limited opportunities for relievers to pitch, but the bullpen temporarily will gain a member, assuming No. 5 starter Todd Wellemeyer misses his next turn due to scheduled off-days Thursday and Monday. Rookie right-hander Waldis Joaquin, who hasn't pitched since April 16 at Los Angeles, looks like the most vulnerable candidate for demotion.

Schierholtz remains in eight-hole

SAN FRANCISCO -- Though Nate Schierholtz was coming off a career-best hitting performance, Giants manager Bruce Bochy decided Friday to continue batting the right fielder eighth.

In 12 starts this season, including Friday, Schierholtz has hit eighth eight times, seventh three times and sixth once.

Schierholtz went 5-for-5 on Wednesday against the Philadelphia Phillies to lift his batting average to .378. He had hit safely in nine of his previous 11 games, posting a .395 average (15-for-38) in that span, and he ranked third in the Major Leagues among left-handed hitters with a .429 average (6-for-14) against lefty pitching.

A No. 8 hitter's productivity can have a resounding impact upon the offense, since his reaching base insures that the pitcher won't lead off the following inning and hastens the approach of the top of the batting order.

"He's having success there and I don't want to mess with that because that's a big spot in the order," Bochy said.

Bochy indicated that he would consider elevating Schierholtz in the batting order if he stays hot for a one- or two-week stretch. "If it's over a long period of time, that's when you make a move," Bochy said.

Louisville native Wellemeyer ready for Derby

SAN FRANCISCO -- Todd Wellemeyer fully understands the significance of the first Saturday in May.

Born and raised in Louisville, Ky., the Giants right-hander knows all about the mystique and pageantry surrounding the Kentucky Derby, which is scheduled for its 136th running on Saturday.

Wellemeyer, 31, recalled the buildup that would start two weeks before the race, including air shows, hot-air balloon races and steamboat races.

"It was awesome," he said.

Wellemeyer attended the 1993 Derby, won by Sea Hero. Since then, baseball has dominated his spring weekends. But he remains connected with what's going on at home.

"All my buddies are there right now," said Wellemeyer, who hopes to organize a Derby pool among his teammates. "My brother's there; my parents are having a party; my aunt and uncle are having a party. I get to hear about all of them."