In a press release today, the Diamondbacks confirmed the rumored agreement between the club and 23-year-old Japanese amateur Shumpei Yoshikawa. The right-hander will report to Salt River Fields for instructional league play.

Per reports from Nick Piecoro of the Arizona Republic back in August, Yoshikawa will receive a signing bonus of $650K in an agreement that seems to violate the norms of player movement between Japan and MLB. Historically, MLB clubs have mostly given Nippon Professional Baseball teams the first right of refusal when it comes to signing Japanese amateur talent, so the deal could still be seen as controversial over a key technicality. Yoshikawa went undrafted by the NPB out of high school, but while pitching for a team in Japan’s industrial league, the righty had performed well enough to vault his stock into prospect status territory ahead of the NPB’s upcoming draft. There’s a debate as to whether the Diamondbacks violated protocol, or whether they simply made a savvy move and caught other MLB teams napping.

It’s worth noting that Yoshikawa wouldn’t have signed the deal if he didn’t want to leave the country. After all, his ceiling for potential earnings is higher in the US if he’s able to deliver on his potential, and every NPB team had a clear shot at him out of high school and chose to pass on it. And, technically, he isn’t the first player to make such a decision — as Piecoro points out, 16-year-old Kaito Yuki bypassed high school entirely to sign with the Kansas City Royals. It stands to reason that if this type of trend continues, and Japanese amateurs continue to be enticed by the earning potential of leaving for American baseball at a young age, it could have an impact on the quality of play in Nippon Professional Baseball.

Yoshikawa stands 6’1″ and has a three-pitch arsenal that includes a splitter, slider, and a fastball that averages in the low-90s, an American League scout told Piecoro. According to the scout, Yoshikawa “profiles as a potential back-of-the-rotation” type of starter in the major leagues.