He will undergo surgery on Wednesday and could be sidelined for nine months.
"Handre was easing back into training, his first phase of final rehab before being cleared to play and was busy with a passing drill when he injured himself,” coach Nollis Marais said in a statement.
“This is pretty devastating for all of us as Handre was a key player for us.”
Pollard was undergoing fitness tests with the Bulls on his first day back at the franchise since returning from Japan where he had been playing club rugby.
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The 21-year-old has won 20 test caps for the Springboks since making his debut in 2014 and was among South Africa’s leading performers when they finished third at last year’s Rugby World Cup.
He recently extended his contract with the Pretoria-based Super Rugby franchise until 2019 but was allowed to play in Japan for three months after the World Cup. The Bulls start their Super Rugby campaign on Feb. 27.
(Reporting by Mark Gleeson in Cape Town,; Editing by Ed Osmond)
