His goal is to practice by the end of week, which, in his eyes, would mean he could play Sunday.
"I understand that it's a process and all depends on how my body feels," Campbell told ESPN on Monday night at his annual CRC Foundation fundraiser dinner in Scottsdale. "The process right now is just listening to my body and just to see how it progresses over the next few days."
Campbell's initial prognosis was one-to-three weeks. Sunday marked a week since Denver's Julius Thomas injured Campbell with an illegal chop block. The end of the second week would be in Oakland and the third would conclude at home against Philadelphia on Oct. 26.
The process of returning from a strained MCL in a week is different for Campbell than that of a player less agile on the field, such as an offensive lineman, he said. His knee is feeling "way better," but he feels the injury is going to linger.
"I guess the biggest thing is making sure the muscle or ligament reattaches and gets strong enough where it won't re-injure itself," Campbell said. "That's the hardest part, so I won't re-injure myself. Once I get through that point, it's just tolerating pain and being able to play."
On Monday, Arians was asked whether he expects Campbell against the Raiders.
"There's a chance," Arians said. "But it's a very slim one, I think."
Watching Sunday's win from the sideline was tough for Campbell, who only missed four games in his first six seasons. It was harder, he said, knowing he was just starting to find a rhythm that could've taken him straight to the Pro Bowl.
He had 16 tackles, a sack and an interception, in the first four games this season, in which Arizona went 3-1.
"It's frustrating because I felt like I was just getting into the groove," Campbell said. "I felt explosive. I felt like I was getting to that mentality where I could dominate. Really felt in Denver, that second half I was going to dominate.
"Things happen and the beauty of it is whenever I do get back, it's still a lot of football left to be played. I can still do what I want to do and help the team win games."