Ireland are facing an out-half injury crisis ahead of Saturday's autumn finale against Australia with captain Johnny Sexton doubtful and Joey Carbery ruled out.Sexton is still struggling with the dead leg he suffered against South Africa while Carbery has returned to Munster to complete his return-to-play protocols after he was caught in the head by Albert Tuisue’s shoulder in the win over Fiji.Andy Farrell has not called up a replacement for Carbery, which could open the door for his Munster team-mate Jack Crowley, who came off the bench for his Ireland debut in Saturday's 35-17 victory.Head coach Farrell has a lengthy injury list ahead of Ireland's final Test of 2022, with a hamstrung Robbie Henshaw having returned to Leinster for treatment.James Ryan, Andrew Porter, Josh van der Flier and Hugo Keenan are all carrying knocks and will all be monitored across the early part of this week, as will skipper Sexton.The IRFU said the quintet "will be re-integrated into training according to their individual management plans".Bundee Aki could feature against the Wallabies after serving a seven-week suspension while Jimmy O’Brien will train with the Ireland squad on Tuesday after completing his HIA process.O’Brien’s Leinster team-mate Joe McCarthy returns to the squad, having completed his return-to-play protocols after suffering a head injury in Ireland A’s defeat to a New Zealand XV.Ireland are chasing a 12th successive home win when they face Australia on Saturday night, which would equal the record set during Joe Schmidt’s time as head coach.Ireland squadBacks (15)Bundee Aki, Robert Baloucoune, Caolin Blade, Craig Casey, Jack Crowley, Jamison Gibson-Park, Mack Hansen, Hugo Keenan, Michael Lowry, Stuart McCloskey, Calvin