Masahiro Tanaka, the 25-year-old pitching ace from Japan, is officially up for grabs to Major League Baseball teams. To get him, they will have to go through Casey Close, the prominent baseball agent at Excel Sports Management who also represents Derek Jeter and Mark Teixeira of the Yankees and pitchers Clayton Kershaw and Zack Greinke of the Dodgers.

Tanaka, who was 24-0 with a 1.27 earned run average during the regular season for the Tohoku Rakuten Golden Eagles, was under contract, but the team relented this week and allowed him to leave for the majors. The team that signs Tanaka will have to pay Rakuten $20 million as part of the posting-fee system in place for Japanese players coming to M.L.B. The payment can be made in installments.

The period to negotiate for Tanaka’s rights ends on Jan. 24.

Major League Baseball said Thursday that Tanaka would be represented by Close, 50, who has handled several of the sport’s top players in his two decades as an agent. He previously worked at IMG and Creative Artists Agency, representing Ryan Howard, Ben Sheets, Kenny Lofton and others. He joined Excel in 2011.

Before becoming an agent, Close was a minor league player for the Yankees. He was drafted in the seventh round in 1986 and played for three seasons at Oneonta, Albany-Colonie and Columbus before asking for his release and moving to the Seattle Mariners’ top minor league team in Calgary.