The Hokkaido Nippon Ham Fighters of Japan's Pacific League have until 5 p.m. ET on Dec. 20 to accept a bid from a major league team for pitcher Yu Darvish.

Bidding for the posting fee closed Wednesday, and the U.S. commissioner's office said it will notify its Japanese counterpart of the amount of the highest bid, but not the identity of the major league club that made the offer.

The Toronto Blue Jays and reigning American League champion Texas Rangers are considered the front-runners the 25-year-old Darvish, a six-foot five right-hander who had an 18-6 record with a 1.44 earned-run average and a league-leading 276 strikeouts in 2011.

Boston and the New York Yankees are also thought to have shown interest.

"[Darvish] is a young man out of Japan that we know has a lot of talent," Yankees manager Joe Girardi told "Whenever the Yankees have a chance to get better, we investigate all of our leads. He's someone that we have followed closely, and we'll see what happens."

If the bid is accepted, MLB will announce the team that won the rights, and that club will have 30 days to agree to a contract. The posting fee will be paid only if an agreement is reached with Darvish's agents, Arn Tellem and Don Nomura.

If no deal is reached, Darvish returns to the Fighters for another season and the Fighters must return the posting fee to the MLB club.

Darvish, who reportedly throws seven pitches including two- and four-seam fastballs as well as a cut fastball and a bevy of off-speed stuff, pitched in the 2008 Beijing Olympics and first gained notoriety in the U.S. in 2009 when he led Japan to a World Baseball Classic title.

It's believed he could immediately slide into the top of a major league starting rotation.

In 2006, Daisuke Matsuzaka drew a $51.1-million US posting fee from the Red Sox, who signed him to a six-year, $52-million contract, taking the total package to more than $100 million.

With files from CBC Sports