Hisashi Iwakuma's agent has hit back at the Oakland Athletics, saying they were insincere in their efforts to sign the Tohoku Rakuten Golden Eagles right-hander on Wednesday.

"Their offer was low, and they weren't sincere," Don Nomura said, a day after the 30-day negotiating period with Oakland came to an unfruitful end. "They thought we would just cave in at the end, but we didn't want to set a bad precedent for the next player who goes."

Rakuten will get back the 29-year-old Iwakuma for next season, while Oakland gets back the $19.1 million posting fee. Iwakuma qualifies for free agency next year.

Nomura said the Athletics never really strayed from their first offer of $15.25 million over four years, which he took as a sign of disrespect and a lack of desire to bring Iwakuma on board.

And Nomura said because Iwakuma could become a free agent next year, Oakland did not appear to be that bothered whether a deal could be reached or not.

"There wasn't a massive difference to what they offered initially," Nomura said of the Athletics' final offer, which he did not divulge. "They knew he was just one year away from free agency, and they never showed any respect."