Ireland coach Andy Farrell said on Tuesday he had yet to rule out any of his squad's injured players from next week's November opener against world champions South Africa.
Recently installed as the number one men's team in international rugby union, Ireland begin their end-of-year campaign against South Africa in Dublin on 5 November, with Fiji and Australia also visiting Lansdowne Road next month.
The South Africa match will be Ireland's first Test since they completed a stunning 2-1 series win away to New Zealand in July.
Farrell, however, faces several tricky decisions over whether to pitch players who are at varying stages of recovery into an encounter with a Springbok team renowned for their all-round physicality.
Fullback Hugo Keenan, scrumhalf Jamison Gibson-Park and prop Tadhg Furlong are among those trying to overcome injuries, although Keenan and Gibson-Park will be reintegrated into training this week.
Ulster's national squad contingent of Robert Baloucoune, James Hume, Rob Herring, Michael Lowry, Stuart McCloskey, Tom O'Toole, Nick Timoney and Kieran Treadwell returned from South Africa on Monday.
The Irish Rugby Football Union said "they will be managed over the coming days" following recent illness issues experienced by the provincial squad during Ulster's recent trip to South Africa for United Rugby Championship games.
"Some players don't need that much game time. Some players are able to just hit it straight from the word go, some players need five or six games to hit the ground running," Farrell told reporters.
"It's up to us to assess that. We are not a massive playing group as well, so needs must at times.
"Certainly, nobody is ruled out at this stage."
Ireland have won six of their last 10 Tests
springboks
Rugby
Michael Lowry
Kieran Treadwell
Andy Farrell
Stuart Maccloskey
Robert Baloucoune
James Hume
Rob Herring
Tom Otoole
Nick Timoney
Hugo Keenan