Young, who won the last of his four caps just over a year ago, has delivered a number of outstanding displays for Cardiff this season, but is now unlikely to play again until April due to a torn calf muscle.
“Cardiff Rugby can confirm Thomas Young will be out of action for up to three months after suffering a torn calf,” the Welsh region said in a statement.
“The in-form flanker limped off during the second half of last weekend’s United Rugby Championship clash with Scarlets. He will now begin his rehabilitation.”
Cardiff full-back Liam Williams, meanwhile, is following return-to-play protocols after going off for a head injury assessment during the Scarlets match. Their international tight head prop, Dillon Lewis, is currently unavailable for selection due to injury and has not played since mid-December due to a knee problem.
Also struggling to be fit for Warren Gatland’s first game in charge since his return to Wales, against Ireland on 4 February, is the Gloucester speedster Louis Rees-Zammit. He suffered an ankle injury during his team’s Gallagher Premiership defeat at Leicester on Christmas Eve.
Gloucester’s current estimate on his return is mid-Six Nations.
