SCOTTSDALE, Ariz. -- The scene has changed for Todd Wellemeyer, but not the situation. He'll again receive the chance to help a pitching rotation validate its status as one of baseball's best.

After becoming the only Giant to pitch seven innings in a Cactus League game, a mini-feat he accomplished in San Francisco's 5-3 loss Tuesday to the Chicago Cubs, Wellemeyer was asked how he felt to join the distinguished starting staff of Tim Lincecum, Matt Cain, Barry Zito and Jonathan Sanchez.

"I came from a really good rotation," Wellemeyer said, referring to the St. Louis Cardinals. Sounding brash and diplomatic from one sentence to the next, he added, "We thought we were better than these guys the whole time anyway. But to go from where I was to here, I'm lucky to be part of such talented guys."

On paper, deciding whether the Giants or Cardinals have a better rotation isn't easy. St. Louis counters San Francisco's contingent with Chris Carpenter and Adam Wainwright, Lincecum's rivals for last year's National League Cy Young Award, as well as Brad Penny, Kyle Lohse and Jaime Garcia.

"We're going to have to prove it," Wellemeyer said. "I know they're solid over there. ... Last year's over with."

Actually, Wellemeyer doesn't officially know whether he's part of this year's Giants rotation. Manager Bruce Bochy continued to resist naming Wellemeyer as San Francisco's No. 5 starter, despite the right-hander's 2.00 ERA in a team-high 27 innings.

However, Bochy confirmed that Wellemeyer, who allowed Chicago three runs and five hits, will start Sunday's exhibition finale against Seattle at AT&T Park -- the spot that the fifth starter would occupy.

Disabled list still possible for Lewis

SCOTTSDALE, Ariz. -- Manager Bruce Bochy acknowledged Tuesday that outfielder Fred Lewis, bothered by sore ribs in his left side, could open the season on the 15-day disabled list.

That would temporarily ease some the apparently challenging decisions the Giants must make regarding their 25-man Opening Day roster. Shelving Lewis possibly would allow the Giants to keep outfielders John Bowker, Andres Torres and Eugenio Velez initially.

Lewis continued to receive treatment Tuesday and probably won't appear in Wednesday's Cactus League finale against the Los Angeles Dodgers.

Asked about the likelihood of Lewis landing on the DL, Bochy said, "We haven't determined that yet, but that's a possibility. We hope that's not the case. We hope tomorrow he shows up and feels a lot better."

Lewis, 29, is batting .222 with a .317 on-base percentage and a .528 slugging percentage.

Confident Rowand sizzles against Cubs

SCOTTSDALE, Ariz. -- Aaron Rowand was impossible to ignore Tuesday.

Rowand went 3-for-3 with two doubles and would have had a third double but was thrown out trying to stretch a fifth-inning hit. He also ranged far to his right in the first inning to snare Derrek Lee's drive to left-center field.

Rowand ranks among the Majors' springtime leaders with a .479 batting average.

"He's playing with a lot of confidence right now," Giants manager Bruce Bochy said. "You can tell he's seeing the ball well."

Rowand's concerned less with his statistics and more with repeating his improved hitting habits -- straightening his stance, maintaining his balance and keeping his head still.

"Whether I had an awful spring or a great spring, to me it wasn't about how many hits I got," said Rowand, who has a team-high 23 hits. "To me it was about getting myself into that good position to hit."

Ishikawa gets work in left field

SCOTTSDALE, Ariz. -- Travis Ishikawa continued to try to diversify himself Tuesday by playing left field in a Minor League exhibition.

Ishikawa, the Giants' backup first baseman, has spent seven innings in left during Cactus League games since late last week but hadn't received any challenging plays. Appearing in the Minor League game enabled him to receive more time in left and get some extra at-bats.

Ishikawa has scant experience in left as an amateur or professional, but to simplify roster management, the Giants obviously would prefer to be able to use him at more than one spot.

"For a big man, he runs better than you think," Bochy said. "Depending on what happens during the season, I'd like to have a little more flexibility with Ishi."

Giants send Casilla to Minors camp

SCOTTSDALE, Ariz. -- The Giants reassigned right-hander Santiago Casilla to Minor League camp, trimming the spring roster to 38 players.

Casilla, formerly of the Oakland A's, recorded a 5.40 ERA in four relief appearances.