The winger is to go under the knife to repair a cartilage problem in his right knee.
Ospreys Head Physio, Chris Towers, confirmed:
"We've spoken to several specialists and the view is that it is in Hanno's best interests to have the surgery now. We've taken a long term view on what is best for Hanno's career moving forward.
"At this stage we are probably looking at a post-op rehab process of around five to six months, it's not something we can rush."
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