Chris Lowrey accepts it will be a tough ask, but he has little fear about doing a non-specialist job when the underdog Blues take on the Queensland Reds on Saturday night for a place in the Super Rugby final.

Usually a No.8 or a blindside flanker, Lowrey will fill in as locking partner to All Black Ali Williams at Suncorp Stadium, after Anthony Boric was ruled out for the rest of the competition with injury.

"The transition's quite difficult but it's a challenge I relish," said Boric.

"It's an opportunity to go on the field in a big game against a great side."

Lowrey, who at 194cm concedes 6cm to Boric, said the lineout would probably present the biggest challenge.

"Anthony is a huge asset for us at lineout time," he said.

"I obviously won't be able to fill his shoes exactly, but I'll be doing my best to help out Ali as much as I can and try to get as much pressure off him as possible."

Lowrey and Williams will go head-to-head against two Wallabies in Queensland skipper James Horwill and Rob Simmons.

With No.8 Radike Samo and blindside flanker Scott Higginbotham providing ball-winning options and Adam Wallace-Harrison to come off the bench, the Reds look sure to attack the Blues' depleted lineout.

But Lowrey said Williams would not be a one-man band, citing the likes of blindside flanker Jerome Kaino among the Blues' other targets.

"I don't think he's the only one, Jerome is another threat," he said.

"It's spread right across. The attention gets put on Ali but there's a lot of other good options in our lineout."

Even before Boric's injury against the Waratahs last weekend, the Blues' locking stocks were already down, with Kurtis Haiu taking indefinite leave in mid-season for cancer treatment.

Lowrey also had starts at lock in the wins over the Highlanders and the Hurricanes.

"The first one was a bit out of the my comfort zone, but I quickly adjusted to it," he said.

"I can take a bit of confidence from my performances."

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