Dani Pedrosa will be replaced in the Repsol Honda line-up for this weekend's Australian Grand Prix by 2006 MotoGP champion Nicky Hayden.
A crash during FP2 ahead of last weekend's race in Japan saw Pedrosa launched into the air and resulted in a fractured collarbone for the Spaniard.
Having undergone surgery on Saturday the 31-year-old expects to understand more about his recovery time following a check-up on Wednesday.
Hiro Aoyama replaced Pedrosa at Motegi but his place at Phillip Island will be taken by Hayden, who has been racing for Honda's Superbike team.
"I felt a strong pain for a few days after the operation, but things are starting to get a little bit better now," Pedrosa said in a statement.
"I left the hospital and I have a check-up scheduled for Wednesday. Only after that will I have a better idea about the recovery time and about when I'll be able to get back on my bike."
Hayden added: "First of all my best wishes to Dani, I'm sure he will come back stronger than ever like he always does. For me it's crazy hard work but it's a chance, 10 years after winning my world title, to get back to my old 'dream team'!
"Doing a week-end in Phillip Island on a factory Honda, it's pretty emotional for me to even think about it, and I'm very grateful for this opportunity and the trust that Honda gives me."