Japanese star third baseman Munetaka Murakami is entering the posting system Friday, officially starting the process of one of the most anticipated free agencies of the winter, sources told ESPN.

Murakami, 25, owns the single-season home run record for a Japanese player in Nippon Professional Baseball, having hit 56 in 2022 to break Sadaharu Oh’s record 55, which was set in 1964. A prolific power hitter, Murakami leaves the Tokyo Yakult Swallows with 246 home runs over his eight seasons in Japan.

His slugging prowess is expected to draw widespread interest among Major League Baseball teams this winter. Murakami’s 45-day window to sign will start at 8 a.m. ET Saturday, sources said, ensuring he will sign with a big league team before it expires at 5 p.m. on Dec. 22.

Murakami, who also can play first base, is one of the jewels of a deep class of players expected to come from Asia this winter. Others expected to join MLB teams through the posting system — which facilitates the transfer of players whose rights teams still control from Japan and Korea to MLB — and international free agency include right-hander Tatsuya Imai, first baseman Kazuma Okamoto and right-hander Kona Takahashi. Also expected to return to MLB are right-hander Cody Ponce, who went 17-1 with a 1.89 ERA in the Korea Baseball Organization, and left-handers Foster Griffin and Anthony Kay, both of whom pitched in Japan.

A left-handed hitter, Murakami played in just 56 games this year because of an oblique injury but nonetheless whacked 22 home runs with a .273/.379/.663 slash line. While concerns over his propensity to strike out, and particularly his in-zone swing-and-miss rate, will give teams pause, Murakami’s age and upside are tantalizing enough that his free agency is expected to turn into a frenzy.

The addition of Japanese players has fueled the past two championships, with Shohei Ohtani and Yoshinobu Yamamoto leading the Los Angeles Dodgers to World Series victories. Los Angeles guaranteed more than $1 billion to sign Ohtani as a free agent and pluck Yamamoto from the Orix Buffaloes through the posting system.

MLB teams that sign players through posting must pay a fee to the Asian team from which the player transfers: 20% for the first $25 million, 17.5% for the next $25 million and an additional 15% on every dollar above $50 million.

Murakami is widely expected to fetch a nine-figure deal, with a posting fee of at least $16.9 million on top of it. High-ranking MLB executives scouted multiple games of Murakami this season and emerged impressed, sources said.

In his eight seasons with the Swallows following his debut as an 18-year-old, Murakami hit .270/.394/.557 with a walk rate of greater than 16% and a strikeout rate nearing 26%.