BOSTON — The Boston Red Sox will open the 2008 season in Tokyo, and the World Series champions could be leaving Japan's biggest baseball star behind.

Pitcher Daisuke Matsuzaka might miss Boston's March 25-26 series against the Oakland Athletics at the Tokyo Dome because his wife is expecting to deliver their second baby around that time. Red Sox president Larry Lucchino said the team and the commissioner's office were aware of the potential conflict.

"We're hopeful that their second child will be born at such a time to allow him to participate," Lucchino said Wednesday in a conference call. "We are hopeful, but we do recognize that he has an important obligation with respect to the birth of that child."

Matsuzaka's first child was born in Japan. It's not clear whether the Matsuzakas plan to deliver in Japan or the United States this time.

The Red Sox paid a record $51.11 million for the rights to talk to Matsuzaka last offseason and another $52 million to sign him for six years. He went 15-12 with a 4.40 ERA as a rookie, and after stumbling in his first two playoff starts he won his last two to help the Red Sox win their second World Series in four seasons.

Even if he can't pitch in his homeland, the Red Sox won't be visiting empty-handed. Lefty Hideki Okajima, who was a key part of the Boston bullpen in the regular and postseason, could return to the stadium where he spent most of his 12-year Japanese career.

The Japan trip had been in the planning for months as baseball officials tried to make the trip more comfortable for the players and gain their consent. Lucchino said the team would fly on a "bigger, better" plane, and stop in California on the way back for three exhibition games against the Dodgers and their U.S. opener at the A's on April 1.

Pitcher Curt Schilling said on a Boston radio station the players met last week and discussed their concerns.

"They're trying to build in safeguards around it, and if they can do that, from a travel standpoint, it's a great idea," he said. "I'm not going to pitch over there, so I'm going to have fun."