Bekker took a knock in the Stormers'18-11 win at the Highlanders at the weekend with early reports suggesting that the extent of the injury could seriously hamper his preparations ahead of the first Test against the Lions on June 20.

This latest setback is the second in quick succession for the 25-year-old South African international who had only just returned to the Stormers side after an extended spell on the sidelines with a foot injury.

Bekker's absence would be a heavy blow for Springbok coach Peter de Villiers who sees the 6ft 8in star as a valuable member of his usual matchday 22.

Although unable to break the dominant World Cup winning second row partnership of Bakkies Both and Victor Matfield, Bekker is usually among his country's replacements and is the favoured alternative if Botha or Matfield are unavailable for selection.