"Our two young locks are really stepping up in that area. We're just going to have to fight fire with fire and we back ourselves to do so."
Loose forward Kaino is out for up to another five weeks after knee surgery, but lock Tuipulotu is nearing a return from a back injury according to assistant coach Steve Jackson.
"Potentially he could be back next week so there are pleasing signs there on his progress," Jackson said.
It's possible that Tuipulotu could play a club game rather than play for the Blues against the Cheetahs at Eden Park next Friday.
A good start by the Blues against a struggling Waratahs team could pave the way for the giddy heights of two away victories in a row. Umaga's men proved with their bonus point victory over the Brumbies, which bizarrely was in the balance until the final seconds, that they are gaining the patience and resilience to put away what must be considered lesser teams.
Another win is very much in their grasp, but questions will remain about their ability to perform under pressure and scrutiny. Another good win would solidify their presence in the top eight which would bring more pressure again.
But the Waratahs have issues themselves. Their hard-fought win against the Reds last weekend allowed them to break a three-matching losing streak and they are struggling for form and confidence this season under Kiwi coach Daryl Gibson despite the undoubted quality in their side, including Wallabies Michael Hooper and Israel Folau.
Their woes are a microcosm of the Australian game; a lack of depth and competition for places through complacency or disorganisation by the governing body leading to poor results which has in turn led to public apathy.
But in loose forward Hooper the Waratahs have a hard working and at times inspirational skipper, a player Jackson described as a "nuisance" who will expose any Blues' mistakes at the breakdown.
"They're similar to the Brumbies; a set piece team," Jackson said. "They work a lot off their lineout so we need to nullify that or give them poor quality ball.
The Blues have welcomed back first-five Piers Francis from a wrist injury, with Bryn Gatland dropping to the reserves bench.
Outside back Melani Nanai has remained there in an otherwise unchanged line-up, but Jackson confirmed he was close to a starting spot after an excellent cameo at GIO Stadium last weekend.
"In the end Michael Collins has been doing a job and when teams are starting to tire, as you've seen, bringing Melani on can really open up the game for us."
The Blues team to play the Waratahs at Allianz Stadium on Saturday, kick-off 9.40pm is:
1. Pauliasi Manu, 2. James Parsons (c), 3. Charlie Faumuina, 4. Gerard Cowley-Tuioti, 5. Scott Scrafton, 6. Steven Luatua, 7. Blake Gibson, 8. Akira Ioane; 9. Augustine Pulu, 10. Piers Francis, 11. Rieko Ioane, 12. Sonny Bill Williams, 13. George Moala, 14. Matt Duffie, 15. Michael Collins.
Reserves: 16. Matt Moulds, 17. Ofa Tu'ungafasi, 18. Sione Mafileo, 19. Leighton Price, 20. Murphy Taramai, 21. Billy Guyton, 22. Bryn Gatland, 23. Melani Nanai.