Any band Tool brings on the road with them is subject to systematic hate regardless of the quality of the band, that's just how it goes. Those people came to see Tool and most are unaware of who the opening bands even are.
The Melvins, Meshuggah, Big Business, Wovenhand, Isis.... all hand picked as openers by Tool and all hated on by a significant portion of the crowd.
I've only seen YOB in tiny venues and I can't imagine an arena doing them any favors.
8/6 - Summer's Laughter ?
8/9 - Boris / SubRosa / Atlas Moth
8/25 - BAT / Shitfucker ?
8/30 - Morbid Saint / Vektor