Hearthpwn

And what would you replace him with?

I think it’s possible, just less optimal. Not 100% sure what The standard Big Priest deck runs exactly atm, but if you have your Statues, as well as things like Lich King or Ysera, it’ll work out decently.

Firebat was using a version with Charged Devilsaur to repeatedly rez it & combine 5-7 attack face damage repeatedly with Mind Blasts as extra finisher fuel if needed.

Not really. If you play Barnes and get Y'shaarj from him, you just win.

Why are you desperate to play it? It's the most boring deck in the game, it makes Pirate Warriors look like Mensans.

Yes, Big Priest is possible without Y'Shaarj, Rage Unbound. He is strong, but not necessary to win games. Obsidian Statue is in my opinion the most important minion in that deck apart from Barnes.

Replace him with another big minion, or simply add a spell to not dilute your minion pool.

You will lose a good amount from the free wins off Ysarj. He's also very effective against druid since they can struggle to remove both bodies.

But it's totally doable. You will want to replace him with a big impact card though. DO NOT pick a value card, because Lich King and Ysera already accomplish this.  Try something that has an immediate impact like Devilsaur. That way against faster board centric decks you can fight onto the board.

Quote from Tykaine >>

Why are you desperate to play it? It's the most boring deck in the game, it makes Pirate Warriors look like Mensans.

I have had a lot of success on standard ladder with Big Priest without Ysh.

I use Lyra as the main substitute -- more chances at summon cards, plus she's a large threat on the board even at 3/5. And depending on your opponent, multiple Lyra appearances can be a nightmare for them as you're already a spell-heavy deck.

Your gameplan becomes more of an outlast than bust out Ysharrj at turn 4 and bank on a win. The main course is N'zoth summoning a buttload of Obsidian Statues at the pivotal moment, usually when fatigue is looming.

Other cards in the deck are The Lich King, Barnes (generally being a PITA, but when he delivers ...), and recently a gold Soggoth the Slitherer. Now you might say, why not melt him for Ysharrj? Well, it's late in the meta for both cards and Soggoth is very problematic even when he's a 5/5 summoned at turn 5 or 6, especially with all the aggro decks running around. He fits in as a substitute when the Obsidians aren't rolling in or you're against a spell user.

Like others have said, if you don't have him, the deck is still playable, just much weaker.  Put in N'zoth and fill your board with statues.... 

I mean, strictly speaking, you COULD do it, but why would you? The entire deck is pulling Y'Shaarj from Barnes on turn 4. If that happens, you win something like 70% of games. If it doesn't, the winrate drops to 40% or so. I won't say it's impossible, it just sort of defeats the purpose. In Wild you can replace him with Kel'Thuzad or Ragnaros and not care at all, as posters above me have said.