Vikings running back Latavius Murray, still recovering from offseason ankle surgery, was placed on the physically unable to perform list Monday.

Murray had surgery six days after signing a three-year, $15 million deal with the Vikings in March. Team officials said they were aware Murray needed the procedure when they signed him as a free agent from Oakland.

However, Murray, who is not currently wearing a protective boot, was expected to be ready for training camp. Upon reporting to camp, he acknowledged he is behind in the backfield competition, having gotten even less work in minicamp than rookie Dalvin Cook.

"They've got the upper hand," Murray told reporters about Cook and Jerick McKinnon. "They've been out there practicing. Dalvin, he's been in the system. When you're in it, you learn a lot."

Murray's absence, however brief or extended, opens the door even wider for Cook. McKinnon, with the bulk of last year's carries, gets to make his case, as well.

Murray, 6-3 and 230 pounds, scored nine touchdowns from inside the 5-yard line for the Raiders last season. Short-yardage situations were where the Vikings' struggles were most glaring in 2016. Murray rushed for 788 yards and 12 touchdowns, in addition to catching 33 balls for 264 yards, despite battling an ankle injury. He also had ankle surgery as a rookie in 2013 and missed the entire year.

"He's had to deal with these types of things in the past," said offensive coordinator Pat Shurmur. "He is very in tune with what we're doing mentally. He asks great questions. He made some suggestions on things too, and helped teach it. So, he's right there mentally. For him it's going to be a matter of getting his body back in and around the ankle and get out there playing. He's got to get used to his ankle and body again."

Murray could still be activated this preseason. It's unclear whether he needs days, weeks or longer to get healthy. If he remained on PUP after the preseason, he'd be placed on the regular season PUP list and would have to sit out the first six weeks of the season.

In the meantime, Cook is expected to take the lead in replacing Adrian Peterson, who starts anew in New Orleans. Cook, the second-round draft pick, has an opportunity to make an immediate impact and upgrade the position from a year ago.