Northampton flanker Tom Wood will miss the restart of the Premiership season after he was diagnosed with a pulmonary embolism - also known as a blocked blood vessel - in July.
The ex-England international, 33, was treated at Northampton General Hospital and on Monday received clearance to resume non-contact training.
Saints face Wasps on 16 August in their first game after the Covid-19 pandemic.
The club hope Wood can make a full recovery before the end of the season.
"We're naturally disappointed that Woody will not be available for when things kick off again on 16 August," said Northampton director of rugby Chris Boyd.
"But he's an excellent professional and we know he'll rehab diligently to hopefully be back in contention before the end of the current season."
The former Worcester Warriors man has been with the club since 2010.