The Rangers appear to making a high-priced gamble on Yu Darvish. Reuters

Negotiations between Japanese standout pitcher Yu Darvish and the Texas Rangers are nearing critical mass as Wednesday's 5 p.m. deadline for the the two sides to agree on a contract moves closer.

The Rangers have paid a $51.7 million posting bid to Darvish's Japanese team the Hokkaido Nippon Ham Fighters, wanting to strike a deal with Darvish similar to the six-year, $52 million deal that the Boston Red Sox struck in December 2006 with Daisuke Matsuzaka. (Reuters/Mike Blake)

According to reports, the length of the contract remains the main stumbling block.

Darvish, 25, is seeking a five-year deal, while the Rangers want to sign him to a six-year contract, after paying a $51.7 million posting fee to the Hokkaido Nippon Ham Fighters for the rights to negotiate. The Rangers apparently want to sign Darvish to a similar contract to the one the Red Sox struck with pitcher Daisuke Matsuzaka in 2006.

Boston's posting bid for Matsuzaka was $51.1 million, and since the Rangers paid a higher posting fee for Darvish than the Red Sox had paid for Matsuzaka, the Rangers seem intent to offer a similar six-year deal, but for less money.

Another option for Texas would be to include a lucrative sixth year of the contract, or an option for that year, with a buyout. With that said, Darvish would still seem to have the leverage in the negotiations whether the offer is five or six years.

Darvish would make more in free agency after five years, but if he and the Rangers were to agree to the six-year deal, then the compromise would likely come at a premium that would push the value of his deal well beyond that of Matsuzaka.

If the Rangers and Darvish cannot strike a deal by the deadline, Texas will receive its $51.7 million posting fee back and Darvish would return to the Fighters, though it remains likely that a deal will be made.

According to Jeff Passan of Yahoo! Sports, the Rangers are keeping their options open, as blockbuster free agent slugger Prince Fielder is still available.

Fielder has reportedly met with the Rangers in recent days. Jim Bowden of ESPN.com said on Twitter that a Sunday meeting between the two sides went extremely well. Bowden has suggested that the Rangers could possibly sign both Fielder and Darvish.

After losing starter C.J. Wilson to the Los Angeles Angels, the Rangers have a large void to fill in the rotation. Darvish would likely vault to the No. 2 starter with the Rangers should he sign with the club.

Darvish is coming off career-high statistics with in Japan. The right-hander had an 18-6 record with a 2.95 earned run average to go along with 276 strikeouts.

With the Angels also signing superstar slugger Albert Pujols in the offseason, the Rangers would be able to perhaps keep pace with Los Angeles by adding Fielder, who had perhaps his best season in the Majors. The first baseman finished the season with a .299 batting average, and hit 38 home runs with 120 runs batted in.