Major League Baseball is withdrawing its proposal for a new bidding system with Japan, making it uncertain whether prized pitcher Masahiro Tanaka will be on the market this off-season.

MLB chief operating officer Rob Manfred said Japanese officials had not acted quickly enough on MLB's proposal for a new agreement and that a new proposal will be forwarded.

"We warned them, told them if this sat too long, there could be shifting winds out there, and suffice it to say there are shifting winds," Manfred said.

Under the so-called "posting system," agreed to in December 1998, more than a dozen Japanese players have moved to MLB before the nine years of service time they would have needed to become a free agent. Under the system, MLB clubs submit bids, and the highest bidder has 30 days to reach an agreement with the player.

Boston obtained pitcher Daisuke Matsuzaka from the Seibu Lions before the 2007 season for $51.1 million US, and Texas got pitcher Yu Darvish from the Hokkaido Nippon-Ham Fighters before the 2012 season for $51.7 million. Those figures don't include the players' contracts with the new teams.

"I think the concerns with the system was it was a blind bidding process that led to inflated numbers," Manfred said, "and that those inflated numbers make that market unavailable to a broad cross-section of our teams."

Tanaka, a 25-year-old right-hander, went a 24-0 with a 1.27 earned-run average during the regular season for the Rakuten Golden Eagles of Japan's Pacific League.

Without an agreement, Japanese players would not be able to sign with MLB until they had nine years of service time

"If that's the way we get Japanese professionals, I think that the 30 major league clubs are prepared to live with that result," Manfred said.