But he has been ruled out for three months after suffering the injury at the Aviva Stadium in the closing stages of the match, after coming off the bench to replace Conor Murray.
He fell awkwardly beneath a tackle and was administered oxygen before being carried off.
It was not the only injury concern for Ireland with Reddan's Leinster teammates Fergus McFadden and Brian O'Driscoll also picking up knocks.
"I've never experienced an injury run like this, but you work your way through and I spoke to (captain) Jamie Heaslip about it and we agreed not complain," said Ireland coach Declan Kidney.
"We took a conscious decision that we wouldn't complain about things. Other people are worse off than we are, plus it's such an insult to the lads coming on and having a huge go."
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