The Vikings' secondary was a question entering the season. It became a major concern in Sunday's 31-27 loss to the Cleveland Browns.

Cornerback Chris Cook suffered a groin injury in the first quarter and did not return. His backup, A.J. Jefferson, left the game because of an ankle injury after getting beat on a 47-yard touchdown catch by Josh Gordon.

Safety Jamarca Sanford left the game in the second half because of a hamstring injury. By the end of the game, the Vikings were forced to use three backups in the secondary.

"You don't want to start getting into your depth this early in the season," Coach Leslie Frazier said.

Marcus Sherels, the team's fifth corner, actually played decent in relief, finishing with a team-high eight tackles to go along with two pass breakups.

"Sherels did a good job," Frazier said. "He made some plays, got his hands on some balls, really competed hard like he always does and put himself in a good position. I thought [safety Andrew] Sendejo did some good things as well when he got in there. Those guys, they stepped up and tried to make some plays."

The coaching staff elected to play Sherels and Josh Robinson as the cornerbacks in base defense and not Xavier Rhodes because the rookie is strictly playing on the left side in the nickel package.

"He's getting a ton of reps in the nickel defense because we're in nickel a lot," Frazier said. "It worked out fine the way we did it."

It's unclear if the injured players will be available next Sunday against the Steelers in London. Cook, in particular, has struggled with injuries throughout his career.

Asked if he thinks he'll be able to play, he said, "Not sure."

Run game stuffed

Adrian Peterson rushed for 180 yards and three touchdowns against the Browns in the 2009 opener. The Browns won that matchup Sunday.

Peterson rushed for only 88 yards and one touchdown on 25 carries, averaging just 3.5 yards a carry. The Browns entered the game ranked No. 4 in the NFL in rushing defense and had allowed only 2.0 yards per carry in their first two games.

Cleveland loaded the box with eight defenders consistently and the Vikings line had trouble creating any running lanes for Peterson.

"[Teams] are stacking the box a little more, and those guys on the other side of the ball are pretty good," Peterson said. "We have to come out and be consistent. All of these short runs of 5 and 6 yards, that's what you ask for, is the run game being efficient. That opens it up for the pass, and that happened to us. We just had opportunities that we just did not take advantage of. That's just what it comes down to."

Peterson also lost a fumble for the second consecutive game. On the play, he found a big hole up the middle early in the third quarter, but linebacker D'Qwell Jackson knocked the ball out of his arm.

Welcome back

Browns receiver Josh Gordon missed the first two games while serving an NFL suspension after violating the substance abuse policy.

Gordon didn't exactly ease back into action. The Browns targeted him 19 times — no, that's not a misprint — and he caught 10 passes for 146 yards and one touchdown.

"Obviously he is a game-changer," Browns quarterback Brian Hoyer said. "He is a big guy and can move, go and get the ball, and he also frees up some other guys."

No tanking allowed

The Browns' decision to trade running back Trent Richardson last week prompted plenty of speculation around the league that the team was tanking in order to improve its draft position.

The Browns certainly didn't play like it.

"Well, we're never going to quit," coach Rob Chudzinski said. "The guys in this room aren't that way, I'm not that way. We'll never quit. That's not even in our terminology."

Cleveland got Indianapolis' top pick in 2014 for Richardson.

Etc.

• Browns punter Spencer Lanning became the first player with a punt, extra-point attempt and touchdown pass in the same game since Sam Baker in 1968.

• The Vikings showed a new wrinkle on their first touchdown in the first quarter. On first-and-goal from the 2, nose tackle Letroy Guion paved the way as lead blocker on Peterson's touchdown run.

• After collecting only 10 interceptions last season, the Vikings already have six in three games this season.

• Kevin Williams started his 158th game, passing Hall of Famer Alan Page for most career starts by a Vikings defensive tackle. Jim Marshall (270) holds the team record for most starts by a defensive lineman.

• Vikings linebacker Erin Henderson was credited with two sacks, two tackles for loss, an interception and a pass breakup.

• Vikings rookie linebacker Michael Mauti, a seventh-round pick from Penn State, made his NFL debut.