Northampton's injury crisis could turn Sunday's Heineken Champions Cup quarter-final against Exeter into a farce.

It means the prospect of uncontested scrums and playing with 14 men unless European Cup organisers allow them to sign another prop this week.

Tournament regulations do not permit a new signing at this point.

The club have been badly hit by injury in the front row since the season's restart, with Danny Hobbs-Awoyemi suffering a serious Achilles injury against Bristol last week, while Nick Auterac was also forced off in the same game.

Francois van Wyk hobbled off against Leicester on Sunday, and the experienced Alex Waller is another injury casualty.

Scotland prop Gordon Reid was signed by the club in March, but his deal expired at the end of June.

Under tournament rules, the 16 clubs who have qualified for the quarter-finals in the Champions Cup and Challenge Cups were required to register their squads on or before 1 September.

EPCR have reiterated that the regulations do not allow any further registration of players, leaving Northampton travelling to Sandy Park seriously light on resources.

It is thought none of their tight-head props are able to play on the other side of the scrum, meaning Iyogun must stay on for the whole game otherwise Northampton will be unable to scrummage competitively.

This would result in uncontested scrums with the Saints then forced to sacrifice a player.

"This week we'll have some work to do to find a fit team to put out on to the field," director of rugby Chris Boyd said on Sunday.

"In some positions we're getting down pretty thin."