Ireland international Conor Murray is evoking patient confidentiality to keep his injury under wraps.
Murray, 29, has been left out of Munster's squad for the Champions Cup trip to Exeter on Saturday, but has refused the province permission to disclose details of his complaint.
And despite training with his teammates over the past week, Munster head coach Johann van Graan says Murray wants details of the injury to remain undisclosed.
"I can't comment on Conor at this stage. As soon as we know anything I'll let you guys know," he said after Munster's defeat to Leinster.
Out of action since July, the talented scrum-half is merely listed as having a neck injury the latest injury bulletin from Munster.
It is the second time that Van Graan has alluded to Murray's requests for privacy over his mysterious injury.
"I can't comment on Conor," he told RTE in September. "Upon his request, I can't comment on his injury. He's requested that his information remains confidential. I can't really comment on that.
"I've got to respect that. From the first day we've handled his injury accordingly. We take care of all of our players very well I believe."
British & Irish Lion Murray is out of contract at the end of the season and has been linked with a move to Top 14 side Racing 92 in recent weeks.
He is also a doubt for Ireland's autumn internationals against Italy, Argentina, New Zealand and the USA.