Hiroya, the one time "next Masato" of K-1, is planning a move to MMA. Nightmare of Battle reports that Hiroya will begin training MMA this year, possibly traveling overseas to train starting in the summer. The 19 year old will not entirely give up on his K-1 aspirations for the moment, but will look to broaden his options by taking part in MMA.
If you've only recently started watching K-1, you may not even know Hiroya, but the young fighter was, just a few years ago, a major part of the company's plans. At just 15 he started competing in various special rules fights for K-1 MAX. The plan was for fans to watch this young fighter develop from a very early age so that by the time he was older and a champion, fans would be strongly connected with him and he would be able to step into Masato's shows as the face of K-1 MAX. It didn't work. As Hiroya continued to fight in K-1, it became clear he was having trouble against his increasingly hand selected opponents. The result was an increasing sense of annoyance from international viewers, and apathy from Japanese fans. In 2008, Hiroya won the Koshien tournament, but when he failed to repeat that accomplishment in 2009 (losing to Masaaki Noiri, who has since proven to be a legitimate, top level talent), it effectively ended both his run, and K-1's promotion of Koshien. Hiroya took time off to finish high school, and in the 15 months since that loss has only taken one fight - a largely one sided decision loss to Yuta Kubo in November.
Hiroya has obviously been passed by many of his Koshien classmates including Noiri, the Urabe brothers, and Kizaemon Saiga - all fighters who now stand on their own as more than just teenage fighters, while Hiroya remains something of a spectacle name. At 19, you certainly can't say his time in kickboxing is done, but for him to make a name in this sport, he will need to get clear of the stigma he currently has, and will need to reinvent himself somewhat. A move to MMA could be a big help in that regard.