Can Yasuo ult off Poppy's new ult?

Enemies knocked up are untargetable, so no, Yasuo can't ult off it.

Actually yes he can. Fully charging Poppy's ult knocks enemies back to base where they become untragetable. But if you don't charge the ult up and hit an enemy with it right away upon casting it, it knocks them UP rather then BACK. I believe Yasuo can get his ult off it.

It depends on how long you channel for. If you instantly activate her ult, it counts as a normal knock up so in that case yes, Yasuo can. If you channel if for the knock up/back then no, the knocked up enemies are untargetable.

Yas can not ult off poppys ult.. confirmed in a game today.

They're untargettable when Poppy ults them and they're in the air.

Keeper's Verdict: 100 Mana 140/120/100 sec Cooldown

[Max Charge Range](http://i.imgur.com/EZ6S7ik.jpg)

"First Cast: Poppy channels for up to 4 seconds, slowing herself by 15%. 

Second Cast: Poppy smashes the ground, emanating a shockwave that deals 200/300/400 (+.9 bonus AD) physical damage to enemies around the first champion hit and knocking them a large distance toward their Summoning Platform. The shockwave length and knockback distance increases with channel duration. 

Enemies are untargetable while they are being knocked away."

[Note: If you don't second cast, CD is refunded down to 30 seconds at base] [Note #2: You can also second casting very quickly to a point blank, low distance "knock up" -** targets are still untargetable while in the air even if used this way**.] [Note #3: Max knock back range is about 3000]

By the looks of it. Nope. =/