The Fighters are expected to pay Otani 270 million yen ($2.4 million) this year, up from 200 million ($1.8 million) last season — a lot for a fourth-year player in Japan but far from the highest salary here. The Fighters could offer Otani more to stay, but it still may not be as much as what he could earn in the majors, even with the hard cap on signing younger international players.

According to Sponichi Annex, a Japanese sports newspaper, the Fighters may post Otani after this coming season. This would allow the Fighters to collect $20 million from the team that signs him, and they could avoid having to sign Otani to ever-larger contracts. With the exception of the Yomiuri Giants, the country’s most famous team, almost all Japanese teams are unprofitable and view posting fees as a way to balance their books. In 2011, for instance, when there was no cap on posting fees, the Fighters received a record $51.7 million from the Texas Rangers when the Rangers signed Yu Darvish.

The Fighters declined to comment on Otani’s future.

“The problem for all the teams except the Giants is once the players get successful,” said Robert Whiting, a longtime baseball writer in Japan, “the teams want them to leave because they can’t afford to pay them what they’re worth. That’s what happened with Darvish, Tanaka and others.”

When Tanaka signed with the Yankees, he was not a full-fledged free agent with at least nine years of service, so the Yankees paid his old team, the Rakuten Golden Eagles, a $20 million posting fee. But because Tanaka had pitched seven years in Japan and was older than 23 (the age limit at the time), he was not subject to international signing caps, so he signed a seven-year $155 million contract, far more than he ever could have earned in Japan.

Tanaka advised Otani to head to the United States as soon as he could. “If you have what it takes, I think the younger you are, the better contract you get,” Tanaka said in December.

For all the hype about Otani, major league teams still tread carefully when looking at Japanese players. With only four seasons under his belt, Otani has less wear and tear on his arm than other Japanese pitchers who have moved to the United States. But he has also been dogged by small injuries, and teams must consider how a player’s statistics in Japan will translate to the majors, where seasons are longer and ballparks are bigger.

“For players coming from the Japanese professional league, you have to have recognition of the difference in the ball, the difference in the workload, their travel and obviously the cultural differences,” said Brian Cashman, the Yankees’ general manager, who declined to discuss Otani because he was under contract to another team. “You take all that into account as you project what they could be as they transfer over to the United States.”