Matsuzaka, the MVP of the 2006 tournament, said Thursday he will start preparing for the WBC in December.
"I'll accept the offer if I'm asked to play," Matsuzaka said. "I'll pick up the pace of my training in December so that I won't have to scramble at the last minute."
The right-hander went 3-0 in the 2006 WBC with a 1.38 ERA. One of his wins came in the final against Cuba.
Matsuzaka said he was pleased with his second season for Boston, where he went 18-3.
"I won 18 games, but in the United States people severely look at the way you perform," he said. "I had a fulfilling season, though, with both good and bad experiences."
Yomiuri Giants manager Tatsunori Hara will guide Japan's team.