theblues.co.nz and James Mortimer 27.Mar.2013Getty Images
He was initially expected to be out for around four weeks but scans revealed a more serious tear, meaning the tighthead prop will now be sidelined for at least six to eight weeks.
Veteran All Black hooker Keven Mealamu is also likely to be rested until the match against the Highlanders next week.
After returning to Blues camp last week following an extended break, Kirwan did not want to rush Mealamu back before he was completely ready.
“I’m going to sit down with Kevvie but the likelihood is we should probably leave him out of this week’s game,” Kirwan said.
“If he’s on the bench we have to make sure he can play 80 minutes. You can’t put him on the bench and say we’re going to play you the last 20 minutes because what happens if the hooker gets dinged in the first minute and then we get another calf tear or Kevvie’s not quite ready. He’s a week away so what do we do? We’ve got to put the player first.”