Cook suffered the injury while being tackled in the fourth quarter of the Vikings' Week 2 loss at Arizona and was held out of practice last week. The running back was designated as questionable for Minnesota's home opener against the Seahawks but ruled out before kickoff.
"I woke up and couldn't play," Cook said. "In this league it's either you're going to play or you can't. In this league, guys are flying around and doing all types of stuff and my game is to go be explosive. I can't be out there if I'm not explosive or not able to help my team win a football game. I'd rather the next guy behind me come in and do an extremely good job and step up and do their job."
In Cook's absence, third-year running back Alexander Mattison tied a career-high with 112 rushing yards and caught six passes for 59 yards, another career-best mark.
Cook did not say for certain whether he'll be available for the Vikings' noon kickoff with Cleveland on Sunday at U.S. Bank Stadium but appeared optimistic about his status.
"Attacking my rehab every day real hard," Cook said. "We'll see how this thing plays out, but I'm extremely confident in what we've got going on in the training room and what they're doing to get me back on the field. I'm extremely confident. We'll see how this week plays out and how I respond."
The Vikings put out their lengthiest injury report so far on Wednesday with several new designations. For the first time since he was cleared to return to practice after undergoing a second procedure this year on his groin, rookie left tackle Christian Darrisaw was listed as a full participant. Rashod Hill, Minnesota's current starting left tackle, was given a veteran's day off, along with Patrick Peterson, Adam Thielen and Harrison Smith.
Coach Mike Zimmer said Darrisaw was doing "better" and expected him to double his reps during the team portion of practice on Wednesday. The rookie got about three reps each team period last week while he was still practicing in limited capacity.