"I thought it was good," Zimmer said of Cook's debut, via the team's official website. "He did some good things. I thought he ran behind his pads well for the first time out."
Cook exited early in the second quarter of his first NFL appearance after showing pile-pushing ability between the tackles and pass-catching acumen out of the backfield.
"I'm sure he feels like he could have done more," Zimmer said of Cook. "And he will in the future."
Cook flashing pass-catching skills makes him a three-down back, which the coaching staff was searching for to replace Adrian Peterson.
"It's something that I rely on in my game," Cook said. "Just being versatile, going out there catching balls.
"They split me out wide, released me out of the backfield ... whatever it is, I'll [do it to] help my team win games. That's what they brought me in for, I have to utilize my talent."
The Vikings will likely talk as though the starting running back spot remains up for grabs, but barring injury it would be a shock if anyone other than Cook carried the load in Minnesota to open the year.