The Blues' Super Rugby title hopes have suffered a blow with key attacking weapon Rene Ranger ruled out for the rest of the competition with a hamstring tear.

The Auckland-based team on Wednesday named promising utility Lachie Munro to replace Ranger on the left wing for Friday night's final round clash with the Highlanders.

Ranger suffered the injury in the Blues' 23-16 loss last weekend to the Crusaders in Timaru which cost them top spot in the New Zealand conference and left them needing two competition points against the Highlanders to guarantee a play-off spot.

At halfback, Chris Smylie replaces regular starter Alby Mathewson, who is listed among the reserves.

Coach Pat Lam said Mathewson was recovering from a head knock.

While medical staff were confident that Mathewson would be right by game time, he could not take part in the team's main training session on Wednesday.

Lam said confirming Smylie in the No 9 jersey would allow the Blues to prepare with certainty in that position.

He also said there had been thought of putting loose forward Daniel Braid, who has spent an extended spell on the sidelines with a neck complaint, on the bench.

However, it was decided that Braid would play Auckland club rugby this weekend.

The Blues, who lost top spot in the New Zealand conference with their defeat to the Crusaders, need two points against the Highlanders to guarantee their place in the playoffs.

Blues: Jared Payne, Joe Rokocoko, Benson Stanley, Luke McAlister, Lachie Munro, Stephen Brett, Chris Smylie, Peter Saili, Luke Braid, Jerome Kaino, Ali Williams, Anthony Boric, John Afoa, Keven Mealamu (capt), Charlie Faumuina. Reserves: Tom McCartney, Tevita Mailau, Chris Lowrey, Sean Polwart, Alby Mathewson, Winston Stanley, Sherwin Stowers.

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