Hiroaki Takaya was examined at a hospital in Fukuoka on February 19 and diagnosed with inflammation in his right elbow. He was reassigned to the rehab group on February 20.
[UPDATE 2/22 @ 1:46am]
If the recovery process takes too long, surgery might become an option.
Source: Sanspo 2/21/2018
[UPDATE 2/24 @ 3:41am]
Takaya has decided to undergo surgery to treat the elbow and will most likely miss the start of the season.
[UPDATE 2/27 @ 9:18pm]
The Softbank Hawks announced today that Takaya had surgery on his right elbow at a hospital in Yokohama. He will most likely require about three months for a full recovery.
Source: Sanspo 2/27/2018