Vikings top draft pick Laquon Treadwell was technically active in Sunday's victory over the Titans. He did not, however, make his official NFL debut.

Charles Johnson, Stefon Diggs and Adam Thielen got most of the snaps at wide receiver. Cordarrelle Patterson made a few cameos, too.

Johnson, the man ahead of Treadwell at split end, had only one catch for 5 yards and was a nonfactor, perhaps due to the quadriceps injury that was listed on the injury report. But still no Treadwell in a game where the Vikings couldn't convert trips into Titans territory into touchdowns.

Coach Mike Zimmer explained Monday why Treadwell did not play.

"He still has work to do. We still have to keep getting him going," Zimmer said. "As you've seen, Diggs was inactive for [the first] three weeks last year. We're trying to do things right … and get [Treadwell] ready to go when the time is correct. I think all these young guys — not just him but all these guys — need to learn about professional football a little bit. It's not like you just come in and you're the best player on the field right now."

Treadwell, the 23rd overall pick in the draft, had a solid training camp but an underwhelming preseason, with only six catches for 61 yards. That was not enough to overtake Johnson, who caught a long TD pass from Teddy Bridgewater in the preseason opener, on the depth chart by Week 1.

Treadwell

Zimmer said that when it comes to the development of young players, even early-round picks, they can show flashes of understanding and appear to be ready to play, only to look like a rookie again the next day.

"You think you know [when they turn the corner], but then sometimes they go back around the other corner," Zimmer said. "You just keep plugging away, keep trying to get them better. Keep staying on them, give them extra meeting time. Make sure they're doing the things right, just go from there."

Cornerbacks added

The Vikings added cornerbacks Tre Roberson and Julian Wilson to their practice squad Tuesday, two days after Xavier Rhodes underwent an MRI for his injured right knee.

Roberson was released twice in the span of a few days earlier in September, first during initial roster cuts and again three days later after he was added to the initial practice squad. He went undrafted this spring out of Illinois State.

Wilson went undrafted in 2015 out of Oklahoma, latching on with the Baltimore Ravens before a broken leg ended his rookie season. He appeared in all four preseason games for the Ravens and was waived during roster cuts.

Rhodes was set to return Sunday from a preseason hamstring injury before hearing "a pop," according to Rhodes and Zimmer, while stretching that morning. He was a late scratch against the Titans, giving way to Trae Waynes' second career start.

Zimmer did not elaborate on Rhodes' injury when asked Monday, only saying he did not need surgery. The Vikings' depth at cornerback likely will be tested again Sunday night against the Green Bay Packers.