The Crusaders will be without All Blacks captain Sam Whitelock for up to a month, after the veteran lock suffered a broken finger.
Just a day after the Chiefs confirmed Brodie Retallick will spend up to eight weeks out of action with a broken thumb, his international locking partner Whitelock has joined him on the injury list.
Whitelock, 33, missed his side's 34-19 victory over the Chiefs at Hamilton last weekend and isn't likely to return to action until late April, when the Crusaders travel to Australia for their Super Rugby Pacific tour.
For now, the Crusaders have captain Scott Barrett and Quinten Strange as the only fit senior locks, with Mitchell Dunshea out for the rest of the season, after a knee injury and surgery.
"Sam Whitelock is out for four weeks," Robertson says. "He broke his finger, he had an operation last week.
":He should be back for the Aussie tour, if not a week earlier. It's been a hell of a casualty ward the last few weeks."
Hooker Brodie McAlister is another casualty for the Super Rugby Aotearoa champions, out for up to six weeks with a calf injury.
The news comes as the depth of all New Zealand sides has been tested so far in 2022.
While injuries are nothing new for professional teams, COVID-19 has swept through squads, leaving the six NZ-based teams battling to field competitive sides, as postponements plague the short season.
Robertson is confident in his side's young players, backing the class of 2022 to shine as and when the opportunities arise.
In this case, young lock Zach Gallagher will deputise for Whitelock and Dunshea, and could make his Super Rugby debut on Friday, when the Crusaders host the Highlanders.
"The depth of your squad is always tested," adds Robertson. "This year, we've had more debutants than we have [had] in a number of years and all of them have stood up, so that's the exciting thing.
"We always feel for the players that get injured, that's part of rugby, but for the next guy to step up and perform like they have, we're excited for Zach."
Join us at 7pm Friday for live updates of the Crusaders v Highlanders Super Rugby Pacific clash
