Fourie has suffered a hand injury and bicep tear all within the last 12 months.
Leeds Carnegie flanker Hendre Fourie has been ruled out of action for between four to eight weeks due to a knee injury.
The 29-year-old suffered a grade three tear to his medial knee ligament in Sunday's 35-10 win over London Welsh.
"It's a massive blow to us, he's been playing so well," director of rugby Andy Key told BBC Radio Leeds.
Fourie is set to undergo further scans on his knee to find out the full extent of the injury.
Meanwhile, Leeds have better news in the backs, with the return of Henry Paul.
The former England centre has recovered from a rib injury picked up on Boxing Day against Otley and is expected to feature against Sedgley Park on Sunday at Headingley.
Leeds have had further cause to celebrate this week with the news that back row Calum Clark will captain the England under-20s during the Six Nations.
The 19-year-old has represented England at under-16 and under-18 levels, and made four appearances at last year's IRB Junior World Championship in Wales, where England were beaten by New Zealand in the final.
Clark became the youngest forward to appear in the Guinness Premiership when he made his debut for Leeds against Saracens on 30 September 2007 at the age of 18 years and 112 days.
Key added: "For him to be given the honour of captain is fantastic.
"I think it goes to show how much he was learnt this season, not just as a player, but as a leader.
BBC Radio Leeds has exclusive full match commentary of Leeds Carnegie v Sedgley Park on 774 AM, DAB and online at bbc.co.uk/leeds. The build-up starts at 1450 GMT on Sunday.
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