Ireland have been left sweating on the fitness of star man James Ryan after it was confirmed the Leinster lock could be out for up to three months with a shoulder injury.
The 24-year-old has become a key man in the international set-up since making his Test bow before he'd even pulled on a senior Leinster jersey in the summer of 2017.
Arguably the side's best player, he was even mooted as a possible captain when long-time skipper Rory Best retired after last year's World Cup, although head coach Andy Farrell ultimately bestowed the honour upon the vastly more experienced Johnny Sexton.
A statement on the Leinster website yesterday confirmed that Ryan had required a procedure to correct the injury suffered in training with a recovery timetable set at between 10-12 weeks.
Ireland are, Covid-19 permitting, set to resume their battle for the 2020 Six Nations in 12 weeks' time when Italy are expected in Dublin for a clash that was originally scheduled for early March.
One week later, on October 31, Farrell's men will be heading to Paris to conclude the championship, which they would win by taking maximum points from the two games.
For both Farrell and Joe Schmidt, Ryan and Ulster skipper Iain Henderson have been the first-choice lock pairing, although it is not an area where the senior side have been blessed with particular depth.
When the eventually-postponed Six Nations began back in February, the previously out of favour duo of Devin Toner and Ultan Dillane had been restored to the panel, the former starting against England in Twickenham when Henderson was absent to attend the birth of his child.
To provide another option, Munster's Tadhg Beirne is emerging from a lengthy rehab process owing to a fractured ankle suffered back in December, although Connacht's Quinn Roux isn't expected to be back in full training with his own province until the end of this month.
Of more immediate concern to Ryan, however, will be his absence from a big run of fixtures for his province.
Leo Cullen's side, who were unbeaten when the season was placed on hiatus, will take on Munster at the Aviva Stadium on August 22 when PRO14 rugby resumes before meeting Ulster at the same venue one week later.
Chasing silverware on two fronts - Leinster will meet Mark McCall's Saracens in the Champions Cup quarter finals next month - Ryan will now be absent for the conclusion to the stunted 2019/20 campaign.