Ben Badler has a story up at Baseball America with scouting reports on Shohei Otani, as well as Shintaro Fujinami, another Japanese high school pitcher who is not coming to the U.S., but who may be a better prospect than Otani.
After giving the rundown on Otani, Badler concludes that, talent-wise, he'd be a late first round pick in a normal draft, saying he's comparable, talent-wise, to 2012 late first rounders Ty Hensley and Luke Sims.
Otani is foregoing the NPB draft in order to come to the United States to pitch professionally. He is an international free agent, and his signing bonus would be subject to the international bonus cap for 2012. The Rangers have not spent very much on the international free agent market, and thus have more funds available than most teams to spend under the cap.
While Hensley, a late first rounder, signed for a $1.2 million bonus, Otani's bonus would figure to be bigger, since he's a free agent and will have multiple teams pursuing him.