Yoshinobo Yamamoto is officially on the board.

The Japanese right-hander was posted Monday by the Orix Buffaloes of Japan’s Pacific League, giving him 45 days to sign with a MLB team, beginning at 8 a.m. ET on Tuesday.

The Mets and Yankees are both expected to heavily pursue the 25-year-old Yamamoto, who is regarded among the top starting pitchers in this winter’s free-agent class.

Bidding on Yamamoto could start in the $200 million neighborhood, according to industry sources, with the Dodgers, Red Sox and Phillies joining the list of potential suitors.

Masahiro Tanaka’s seven-year contract worth $155 million, which he received from the Yankees before the 2014 season, is the richest for a Japanese pitcher.

The Mets looked to Japan last offseason in signing Kodai Senga to a five-year contract worth $75 million.

The right-hander rewarded the club on the investment by pitching to a 2.98 ERA with 202 strikeouts in 166 ¹/₃ innings.

But Yamamoto’s ceiling is regarded as even higher.

“It’s legit,” said a major league talent evaluator who has watched both pitchers. “It’s better than Senga. Yamamoto is younger. I think [Yamamoto] has better fastball command. Senga’s cutter and split are probably better, but [Yamamoto] is a better pitcher, which is crazy to say because Senga is really good, too.”

If there’s any concern about Yamamoto it stems from his smallish frame — he’s listed at 5-foot-10 — but scouts are enamored with his command of six pitches, including a sinker he developed this year.

“He’s not a big guy, but his stuff is just nasty and the pitch-ability is a lot better than Senga’s,” the talent evaluator said. “Senga throws hard and he has nasty stuff, but the walks, they get away from him a little at times, where Yamamoto there is a lot more pitch-ability and strike-throwing ability, which may hurt him. He might be in the zone too much.”

Yamamoto has won the equivalent of the Japanese Cy Young award in each of the last three seasons, after leading Nippon Professional Baseball in wins, ERA and strikeouts in each of those seasons.

He just finished a season in which he went 17-6 with a 1.16 ERA with 176 strikeouts in 171 innings.

If the Mets were to sign Yamamoto, it would almost guarantee a move to a six-man rotation next season, allowing extra rest between starts for both Japanese pitchers.

The Mets were diligent in giving Senga extra rest between starts last season — and may continue with that plan next year — and would look to go that route with Yamamoto as a MLB rookie.

As it stands, Senga and Jose Quintana are the only veterans returning to the Mets rotation, meaning the Mets will need multiple starting-pitching additions.

But it’s possible the Mets could look to fill one spot from a group that includes Tylor Megill, Jose Butto and Joey Lucchesi.

Another option, David Peterson, will miss the early part of next season after undergoing labrum surgery in his left hip.

Yamamoto would slot somewhere behind AL Cy Young award winner Gerrit Cole in a Yankees starting rotation mix that includes Nestor Cortes, Carlos Rodon, Michael King, Jhony Brito and Clarke Schmidt.

The deadline for the signing club to submit terms on Yamamoto, under the posting system, is 5 p.m. on Jan. 4.