The Seibu Lions of Japan's Pacific League announced they had accepted the high bid for their prized pitcher, and the major league commissioner's office simultaneously confirmed at the general managers' meetings that the Red Sox had made the offer.
"We're very pleased and excited. We've long admired Mr. Matsuzaka," Boston general manager Theo Epstein said. "Matsuzaka has a real talent. He would be a great fit with the Red Sox organization.
"We're excited to have won this part of the process. We're hopeful we can reach an agreement."
Even before the announcement, general managers had assumed Boston would be the highest bidder in the blind process.
"We'll congratulate the winner and move on," New York Yankees GM Brian Cashman said Tuesday afternoon.
Matsuzaka is represented by Scott Boras, who last year negotiated the deal that moved center fielder Johnny Damon from the Red Sox to the Yankees.
"Pitching, as usual, is at a premium," Boras said.