Kenji Otonari had his lower back examined at a Fukuoka hospital on Thursday and after discussing things with the Softbank Hawks, decided to opt for back surgery. There is still no timetable for his return, but he will likely require about a year for a full recovery.
Otonari told reporters that the problem was not so much his lower back, but the loss of sensation in his legs. He decided on the surgery after having his back examined at a number of hospitals.
While a diagnosis has not been revealed to the media yet, Otanari might be suffering from a pinched nerve due to a tight ligament near his lower back. It could also be a case of ossification of the yellow ligament.
Source: Daily Sports 6/14/2013
UPDATE 6/15 @ 8:46pm -
Otonari is scheduled to go under the knife on the 21st. He will be hospitalized for ten days after the surgery. It could take four to five months for a fully recovery. There is a good chance he will miss the rest of the season.