Taiki Ono left fall camp in Kochi and returned to Osaka on November 12 because of pain in his right knee.
Source: Daily Sports 11/12/2017
[UPDATE 11/13 @ 4:19pm]
Ono started feeling pain in his right knee on November 9. The Hanshin Tigers are concerned because he had surgery on his right knee during his third year of high school. Ono had the knee examined today.
[UPDATE 11/14 @ 3:12pm]
Ono was examined at a hospital in Osaka on November 13 and diagnosed with inflammation in the medial side of his right knee.
[UPDATE 11/19 @ 2:01am]
Ono started playing catch on November 18. He threw the ball indoors at a distance of about thirty meters.
Source: Nikkan Sports 11/18/2017