SAN FRANCISCO — Barry Bonds plans to wear red, white and blue in March.

Bonds has agreed to play for the U.S. team in the World Baseball Classic, adding instant credibility to the inaugural event and perhaps also giving the Giants some cause for concern.

Agent Jeff Borris confirmed that Bonds has told the Players' Association that he intends to participate.

"It's not official," Borris said. "There are still a few details to be worked out. But he has agreed to play."

Union special assistant Bobby Bonilla said Bonds was one of the first players that he called to recruit shortly after the regular season ended.

"I'm ecstatic," Bonilla said. "He pretty much agreed in principle to play without hesitation. I'm just happy he's going to be a part of it.

"It's huge. We need the best player in the game, and we've got him."

Partial rosters could be announced as soon as next week, according to a major league source. Other Giants who could participate include Omar Vizquel and Edgardo Alfonzo (for Venezuela), and Armando Benitez and Moises Alou (for the Dominican Republic).

Player participation was a hot topic at the general manager meetings in November, and the issue is expected to generate more discussion at the winter meetings next week. Chiefly, clubs are concerned about excessive pitch counts.

But the Giants might be risking more than any other team with Bonds' participation, given his age (41) and the amount of money the club has invested in him ($18 million, uninsured).

According to industry sources, teams are not required to give consent or allowed to provide conditions for player participation. The union has not contacted the Giants about Bonds.

Giants spokesman Blake Rhodes said the club would have no comment until rosters are made official.

Bonds will be monitoredclosely this spring regardless of what uniform he wears. He nearly missed all of last season because of three knee surgeries, including one to treat an infection; he debuted on Sept.12 and hit five home runs in 14 games to bring his career total to 708 — six away from tying Babe Ruth for second place on the career list.

Giants GM Brian Sabean said Monday that Bonds has resumed workouts with physical therapist Clive Brewster in Los Angeles; the seven-time MVP's commitment to play for the U.S. team could be a sign he is optimistic about his health.

Also, Sabean said Bonds has not been back to see Dr. Lewis Yocum, another indication he has not encountered problems with the knee.

"I believe he is where he wants to be at this time," said Bonilla, whose friendship with Bonds goes back almost 20 years to their days together in Pittsburgh.

Bonilla said he did not speak to Bonds in specific terms about his level of commitment. But games will include a designated hitter, and Bonilla said he didn't expect Bonds would be asked to play the field.

American players are scheduled to report to camp in Arizona on March 3. First-round Pool B games (U.S., Canada, Mexico, South Africa) will be held March 9-11 at Chase Field in Phoenix and the Giants' spring training home at Scottsdale. The Giants play an exhibition against the U.S. squad on March 5 at Scottsdale Stadium, potentially pitting Bonds against his current teammates.

If the U.S. team advances, second-round games would be held March 13-15 at Angel Stadium in Anaheim; the finals are scheduled for March 18-20 at San Diego's Petco Park.

Bonds has not signed a player participation agreement with the union, but that paperwork is expected to be a formality.

According to Major League Baseball, all players on provisional and active national rosters will be subject to Olympic-style drug testing in accordance with an Anti-Doping Agreement signed by MLB, the Players' Association and the International Baseball Federation.