Australian rugby is short of depth in a few positions and blindside flanker is most certainly one of them.
Michael Cheika and the Wallabies are lucky that Scott Fardy is on hand as he is a world class option at blindside.
But with Fardy set to leave for Leinster at the end of 2017, there are sizeable boots to be filled in 2018 and beyond.
As things stand, here is how the pecking order shapes up.
1. Scott Fardy
No surprises here.
Fardy is the full package and that can't be said about any other blindside in Australian rugby right now.
He carries the ball well, gets through plenty of tackles and applies breakdown pressure with as much nous as most openside flankers.
Add that to his on field leadership and you have a player at the peak of his powers.
2. Ned Hanigan
Featured in the second row discussion last week but is well worth another mention.
His biggest asset are without question, his ball carries.
He offers some quality physicality in his defensive work but doesn't apply the same sort of pressure Fardy does in searching for turnover ball.
That's not part of the required skill set to be a blindside, though, and he has time on his side.
3. Adam Korczyk
Another young gun that is similar to Fardy in the way that he applies breakdown pressure, so much so that he has played openside for the Reds this year.
Carries the ball efficiently when he does get it but has been beaten to a starting gig by Hendrik Tui because he hasn't hit the advantage line enough.
Similar to Hanigan in that he has time on his side and has elite lineout skills on his side.
4. Dean Mumm
Hasn't been in the best of form this year but has featured in Michael Cheika's plans at blindside in the past couple of years.
On current form, may struggle to make the match day 23 ahead of Fardy and one of the aforementioned young guns, should Cheika look to use the June Tests to blood some youth.Unavailable: Jack Dempsey. Would feature in this top four given he started ahead of Hanigan at the top of 2017 but will miss the June Test series due to injury.