Donate with Olympic gold medalist Monica Puig to help Puerto Rico:
Milos Raonic, who retired with injury during his quarterfinal match at Tokyo, says he will have further evaluations when he returns home.
That indicates Raonic will not play next week at Shanghai.
"It was so tough having to retire after one game today in Tokyo. I picked up a strain to the calf. It’s hard to know the extent of it," he wrote.
The Canadian was playing his first event since Montreal, having had minor wrist surgery, and has been frequently injured this season.
Raonic called it a "difficult and frustrating" season, and said he would have liked to have "focused on tennis more rather than chasing help all the time."
But his wrist had not been a problem in his return, he added.
Raonic has also brought on Javier Piles, the former coach of David Ferrer, who accompanied him to the tournament. Raonic has had several coaching changes in recent years, but has kept working with his regular coach, Riccardo Piatti.
Raonic is next scheduled to play the ATP event in Vienna.