Polamalu also had praise for rookie running back Kene Nwangwu, who was a fourth-round pick out of Iowa State.
Nwangwu was singled out for his effort in practice, particularly in coverage on special teams.
"Very bright young man. Explosive. Very cautious of wanting to do things right. I've just got to unleash him," Kenney said. "Be creative, there's going to be sometimes you make a mistake but make it 100 miles an hour and you'll be fine.
"I'm looking forward to it because he's not only doing that, Coach Zim' showed a nice special teams [play on film] where he covered kickoff and was one of the first guys down the field and had a really good collision," he added. "That's what we're about in our room, making plays with or without the football. Be the guy that can just impact. Don't just be out here wearing a uniform."