Crusaders first-five Richie Mo'unga goes down in a heap after attempting to tackle Stormers prop Steven Kitshoff.

A suspected broken jaw could force Richie Mo'unga to take a lengthy break from the Crusaders' Super Rugby campaign.

First five-eighth Mo'unga had to leave AMI Stadium in the final minutes of the Crusaders' 45-28 win over the Stormers in Christchurch on Saturday night, having suffered his injury while attempting to prevent Stormers replacement prop Steven Kitshoff from scoring a try.

Crusaders coach Scott Robertson said Mo'unga was taken straight to hospital for X-rays, but it was too early to say how long he will be unavailable for. If surgery is required, the fringe All Black could potentially be out of action for several months.

MARTIN HUNTER/ GETTY IMAGES Crusaders first five-eighth Richie Mo'unga suffered a suspected broken jaw in the win over the Stormers.

"It was just a head clash," Robertson said. "It was when their reserve prop scored, he took one on the chin. He [Mo'unga] sort of fell off that tackle when they scored. He is away getting X-rays now."

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GETTY IMAGES Stormers prop Steven Kitshoff is a big lad.

Mo'unga, who is pushing for a place in the All Blacks squad following Lima Sopoaga's decision to play in England after Super Rugby, didn't appear to have any blood on his face after tumbling to the ground but immediately signalled for assistance and quickly left the field.

The first-five, who played for the All Blacks in their mid-week match against a French XV in Lyon last November, had a major influence on the outcome of the Crusaders' bonus-point win over the Stormers.

He scored a try, a fine jinking run that embarrassed several defenders in the second half, kicked five conversions in a tricky breeze and insisted on standing flat to force the opposition defence to commit to him rather than getting the easy option of drifting to the next receiver.

MARTIN HUNTER/GETTY IMAGES Richie Mo'unga weaves his way through the Stormers defence in Christchurch.

Mo'unga's bravery in defence was also a bonus, and ultimately cost him when he tried to stop the much bigger Kitshoff.

The Crusaders can take some comfort from having two quality first-fives as cover. Mitch Hunt proved in his first season of Super Rugby last year how cool he can be under pressure. In addition to kicking the long drop goal to beat the Highlanders in Christchurch, he also nailed a late penalty to sink the Reds in Brisbane earlier in the competition.

Mike Delany, who played one test for the All Blacks in 2009, has also been added to the squad this year and will provide insurance.

MARTIN HUNTER/GETTY IMAGES Richie Mo'unga, left, is congratulated by team-mate Mitchell Drummond after scoring a try against the Stormers at AMI Stadium.

Last year Mo'unga was unavailable for around six weeks because he broke his left hand in the Crusaders' first game of the season against the Brumbies, requiring surgery. He also broke his right hand playing for the All Blacks, requiring surgery when he returned to New Zealand.

"It is a shame for him," Robertson said in reference to Mo'unga.

"It is similar to what happened last year isn't it? He broke his hand and Mitch Hunt was exceptional and took that opportunity. We have got that depth.

"Mike Delany - it is for that exact reason why he is in our squad. He is a tremendous player and experienced."

Mo'unga joins fellow All Blacks Kieran Read, Matt Todd, Israel Dagg, Owen Franks, Joe Moody and Tim Perry in the Crusaders' casualty ward.

Blindside flanker Pete Samu had to be replaced in the second half after injuring his shoulder, and midfielder Ryan Crotty was taken off the park because of cramps in his calf muscle.

"We missed Ryan," Robertson admitted. "When he is on the field, he pretty exceptional. He is a key playmaker for us. So we looked after him."