DENVER -- Barry Zito's next start might not generate as much emotion as a Golden State Warriors playoff game, but it could come close.

This Friday, Zito is scheduled to face the Oakland A's, the team with which he built his reputation as one of baseball's top left-handers from 2000-06. Zito, who signed a seven-year, $126 million contract in free agency with the Giants last December, understands that his appearance in McAfee Coliseum in the opener of a three-game Interleague series will generate a mixed reaction.

"There'll probably be some cheers and some boos, same as most people who come back," Zito said Sunday. "I love the fans there and they're great, but they've got to support their team. If they have to boo me, they have to boo me."

Zito amassed a rich store of memories with the A's. He won the 2002 American League Cy Young Award with them, joined them for five trips to the postseason and built numerous friendships. But once he dons his uniform, the spirit of competition will trump everything else.

"I think it'll be like any other team when I'm out there facing them," Zito said. "When we're off the field, it's different. We're all friends and stuff."

Pitching plans: The Giants received good news before the game when right-hander Brad Hennessey, who was sidelined for three games after complaining of a sore shoulder, played catch and reported no discomfort.

"If we had to use him, we could have," Giants manager Bruce Bochy said.

Right-hander Russ Ortiz, who's on the disabled list with an ailing right forearm, threw the equivalent of a between-starts bullpen session and is expected to make at least one injury-rehabilitation start in the Minor Leagues. Bochy said that a final determination will be made Monday or Tuesday, after the Giants evaluate how Ortiz feels following his throwing stint.

Roberts update: Center fielder Dave Roberts, who underwent arthroscopic surgery on his left elbow Friday, intends to do what he can to shorten the estimated six-week period that he'll be sidelined.

"I'm going to try to push the envelope," Roberts said. "Gresh [trainer Dave Groeschner] is already joking with me, saying that I'm going to be a tough patient." Roberts noted that he already has begun performing range-of-motion and light strengthening exercises.

Kevin's cuts: Infielder Kevin Frandsen, who received his third start Sunday since being recalled from Triple-A Fresno on May 3, entered the game hitting 4-for-11 (.364) in that stretch. He notched three singles, a triple and three RBIs in Sunday's contest.

Asked whether playing daily in Triple-A has helped him maintain his swing more easily, Frandsen said that the difference has been minimal.

"My swing doesn't have a lot to it," Frandsen said. "So if something doesn't feel right, I know what it is. You know when your hands just don't feel right or your load's not right. It's real simple. With me, there's not a lot of action, like a double stride, a huge load or a wiggling of the bat."

Dr. Mays: Giants legend Willie Mays will receive an honorary doctorate of humane letters during commencement exercises at Dartmouth College in Hanover, N.H., on June 10.

Coming up: Following Monday's scheduled off-day, San Francisco will play a three-game series in Houston starting Tuesday. The Giants also visited Minute Maid Park exactly a year ago -- May 15-17 -- but they'll have to operate at peak efficiency to enjoy the same result. They swept that three-game series by the unlikely cumulative score of 34-5.

Matt Morris (4-1, 3.11 ERA) will face off with former Cardinals teammate Woody Williams (1-5, 5.10) in the 5:05 p.m. PT series opener.