Ireland have been dealt more injury setbacks with Sean Jansen ruled out for the remainder of their Nations Championship campaign.

The Connacht forward sustained a knee injury in Friday’s 42-12 defeat of Argentina in Dublin and joins fellow back-row pair and long-term absentees Caelan Doris and Jack Conan on the sidelines.

Ireland will also be without captain Dan Sheehan for Saturday’s match against Fiji at the Aviva Stadium as he undergoes a 12-day return to play protocol after sustaining concussion against the Pumas.

With Jansen’s absence further depleting head coach Andy Farrell’s back-row options, uncapped Ulster forward David McCann has joined this week’s training camp, together with Leinster hooker Gus McCarthy.

Another back row, Josh van der Flier (ankle) and wing Rob Baloucoune (cramp) are both hoping to be fit to face Fiji and are being monitored by Ireland’s coaching staff.

Connacht centre Bundee Aki, a late withdrawal from last week’s squad due to illness, is expected to resume full training on Tuesday.

Ireland, who will announce their team to face Fiji on Thursday, take on world champions South Africa at the Aviva Stadium on 21 November before the Nations Championship finals weekend at Twickenham from 27-29 November.