Matt Todd has joined a long list of All Blacks in the casualty ward following the Crusaders' 45-23 loss to the Chiefs last weekend.

As Matt Todd carried his broken thumb into a recovery unit already bursting with All Blacks, rookie Billy Harmon fixed his eyes on the Crusaders No 7 spot.

Although Crusaders coach Scott Robertson is hoping a medical update next Monday will paint a brighter picture, he knows there is a chance All Blacks openside flanker Todd could be unavailable for up to six weeks.

The good news for the All Blacks selectors is that Todd, once healed, should get plenty of chances to add a razor edge to his breakdown ball-hunting skills prior to the three-test series against France in June.

GETTY IMAGES Billy Harmon (C) will make his first start in the No 7 jersey against the Stormers.

The downside of this, of course, is that the Crusaders will be without one of the most dangerous scavengers in Super Rugby. But for Harmon it's the chance he is waiting for, as he prepares to make his first start in the No 7 jersey against the Stormers in Christchurch on Saturday night. Heiden Bedwell-Curtis will provide back-up from the substitutes bench.

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Robertson said Todd, who last year won the tussle with Ardie Savea to be preferred as the back-up to All Blacks incumbent opensider Sam Cane, was unaware how he hurt himself during the 45-23 win over the Chiefs last weekend.

"We don't know, he just came off and said his thumb was sore afterwards," Robertson said. "Doc (Dr Martin Swan) checked it out, said we better X-ray it and it turned out he had a broken thumb.

"It is a bit of a shame because he was in great form. It was just one of those things in rugby. These things are normally a six-weeker, but we are hoping that it is shorter than that."

The impending medical report will state whether or not Todd, who has his hand in a cast, requires an operation.

"They just want to see how it settles over the week and get another scan on it - an MRI," Robertson noted.

Last year All Blacks captain and Crusaders No 8 Kieran Read immediately had a screw imserted in his thumb after breaking it against the Cheetahs in Bloemfontein and was unavailable for around six weeks. He returned to lead the All Blacks in the series against and British and Irish Lions.

The Crusaders now have five All Blacks forwards unavailable because of injury.

No 8 Kieran Read is still recovering from the back surgery he required after the All Blacks' tour of Europe late last year and it's hoped he will return to play in mid-April. Fullback Dagg and props Franks and Moody, who suffered injuries last year and missed the end of season tour, are expected to be fit around mid-April. Prop Tim Perry is expected to be available within weeks.

Robertson was enthusiastic about Harmon's ability to hold his own against a Stormers loose forward unit that is expected to be led by Siya Kolisi.

"He (Harmon) played well at the Tens (Brisbane Global Tens) and was incredible in the pre-season and off the bench as well. He deserves the opportunity, he is confident."

One other change to the side that started against the Chiefs is the switching of locks Scott Barrett and Luke Romano. The latter will make his 100th Super Rugby appearance.

The Stormers, without Springboks lock Eben Etzebeth for up to 10 weeks because of back and shoulder injuries, lost to the Waratahs in dramatic circumstances in Sydney last weekend. Two turnovers off lineout throws resulted in the Stormers conceding a try to flanker Ned Flanigan as the Waratahs escaped with a 34-27 win in the final moments.

Crusaders: David Havili, Seta Tamanivalu, Jack Goodhue, Ryan Crotty, George Bridge, Richie Mo'unga, Bryn Hall, Jordan Taufua, Billy Harmon, Peter Samu, Sam Whitelock (captain), Scott Barrett, Michael Alaalatoa, Codie Taylor, Wyatt Crockett. Reserves: Andrew Makalio, Chris King, Oliver Jager, Luke Romano, Heiden Bedwell-Curtis, Mitchell Drummond, Mitchell Hunt, Manasa Mataele.