Sean Jansen has been ruled out of the remainder of Ireland's Nations Championship campaign with a knee injury, further depleting head coach Andy Farrell's options at number eight.

With Caelan Doris and Jack Conan already injured, Jansen was forced off during Friday's 42-12 win over Argentina in Dublin and will return to Connacht to continue his rehabilitation.

Hooker Dan Sheehan will miss Saturday's home match with Fiji (20:10 GMT) after sustaining a concussion against the Pumas, but the coaching staff are "hopeful" wing Rob Baloucoune (cramp) and flanker Josh van der Flier (ankle) will be available.

Sheehan - squad captain in Doris' absence - is a doubt for the South Africa game on 21 November as he undergoes 12-day return-to-play protocols.

With mounting back-row injury issues, uncapped Ulster forward David McCann has been called up, while Gus McCarthy has joined the squad to boost Farrell's options at hooker.

Centre Bundee Aki, a late withdrawal from the Argentina game with illness, is expected to resume full training on Tuesday.

Farrell said Mack Hansen picked up an ankle problem in the Argentina game but the winger was not mentioned in the Irish Rugby Football Union (IRFU)'s squad update on Monday.

After facing Fiji and back-to-back world champions South Africa at Aviva Stadium, Ireland will travel to Twickenham for a finals weekend fixture.

McCann and McCarthy were originally named in the Ireland XV squad for their fixture against Fiji 'A' in Cork on 20 November.

Tom Ahern (neck), Ethan McIlroy (thumb) and Michael Milne (ankle) have all been ruled out of the XV game, with Fineen Wycherley, Todd Lawlor and Jeremy Loughman called up.