Major League Baseball and Nippon Professional Baseball had a “tentative agreement” in place to allow the Nippon Ham Fighters to post Shohei Ohtani — a lauded pitcher and hitter — for $20 million. However, the players’ union is challenging the system, Jon Heyman of FanRag Sports reports, which will delay Ohtani’s move to Major League Baseball until the matter can be resolved.

The union is challenging future terms for the 2018-2020 seasons. The $20 million that would be posted for the right to negotiate with Ohtani would go to his current team, the Fighters. Due to current rules under the collective bargaining agreement, Ohtani would only receive a signing bonus between $300,000 and $3.53 million. Understandably, the union is concerned about this inequality, despite having agreed to the current terms regarding international players.

According to one of Heyman’s sources described current talks as at a “standstill.”