Sometimes, the mother of invention is simply right place, right time. Running back Kerwynn Williams has taken snaps before in his football career. He played quarterback in high school (surprisingly, Williams said) and at Utah State he was used in some wildcat formations. But with the Cardinals, it really hadn't come up until the week of practice heading into the game against the Vikings.

The Vikings use the wildcat. So the Cardinals were practicing against it with their scout team. Normally, practice squad running back Elijhaa Penny would have served in that role. But Penny wasn't at practice that day, his child being born. So Williams jumped in, and apparently, coaches liked what they saw.

"I guess the rest is history," Williams said.

The next week, Williams had a part in the offensive package. Williams was in the wildcat twice in Atlanta. He handed off to David Johnson for a 16-yard gain on the first play. The second time, Williams broke for a nice 11-yard gain, although it was wiped out on an A.Q. Shipley holding penalty. It "adds a different wrinkle to the offense," Williams said, and there is little question that Williams has proven over his years in Arizona -- even though he has been on and off the roster -- that he can run the ball. That's never really been in doubt, and it flashed again against the Falcons.

As for playing wildcat quarterback, there is also the chance to pass the ball too, right?

"I did have a little bit of the laser back in the day," Williams deadpanned. "It's still there. I've still got the fundamentals."

Williams smiled. "But that's what Carson is for," he added. "He's a great quarterback, he makes a lot of great passes. I don't think they need me to throw the ball."