In a stunning move, six-time Pro Bowler Weddle re-joined the Los Angeles Rams this week for the playoffs, having previously retired after the 2019 season.
The safety will make his comeback against NFC West rivals the Cardinals on Monday, which will be 750 days since his last NFL appearance.
The roster move with Weddle came with the Rams having issues in their secondary.
Jordan Fuller was ruled out for the season due an ankle injury, while free safety Taylor Rapp has not cleared concussion protocol and will miss the game.
That could lead to significant snaps for the 37-year-old Weddle, who quit two years ago after 13 successful seasons in the league.
Rams head coach McVay revealed there are a range of outcomes over how involved Weddle will be in his first game back but is convinced the veteran will be ready.
"He's done a great job," McVay said, per ESPN, when asked about Weddle's progress. "He's brought a great energy. He's a great communicator. He's a great leader.
"He'll be ready to go. What exactly that role looks like, we're still working through, but I do know as a competitor when he's out there, if he's going and he gets into the flow, he's gonna want to go.
"If he's feeling good and there's no risk and we're in a good flow, we'll kind of just take it a snap at a time.
"It's hard for me to realistically put a parameter around it because this is something that's never been done before.
"It could be 10 [snaps]; it could be 30. I think in a lot of instances too, it depends on what kind of personnel groupings we're presenting to the Cardinals' offense as well.
"[Rapp] is a big loss. He's doing everything in his power to get back as quickly as possible, but we have got a lot of confidence in Nick Scott and Terrell Burgess as well."
Weddle discussed his return earlier this week, insisting he had kept physically fit in retirement.
He said: "Even though I haven’t been playing football, I still train like I’m playing football.
"It [returning] was never even a remote possibility ever over the last year and a half because I was pretty much set in my decision and very happy.
"This is by no means me having an itch or anything like that. It was just the opportunity of a lifetime.
"I just kept coming back to I would regret it if I didn’t come and take this chance to try to help out the guys that I love, a coach that I love and try to help this team out, whatever role that is.
"It didn't take much persuading. It was kind of just going through the avenues with all the coaches and reaching out to some players.
"I didn't want to come in and ruffle any feathers or be someone who gets in the way, but once all that was on the same page, it was a no brainer in my mind."
The Rams are at home for the Wild Card game after edging the Cardinals to win the NFC West.
Two games between the teams in the regular season were split, with each team winning on the road (37-20 Cardinals in L.A., 30-23 Rams in Arizona).
Arizona fared well on the road this season, going 8-1, but struggled to a 3-5 record at home.
Per Stats Perform data, in modern NFL history (since 1933), the only other team to have as many as five more road wins than home victories in a season is the Miami Dolphins, who went 6-2 on the road and 1-7 at home in 2010.
