After another lackluster season opener, Adrian Peterson needs a critical combination of patience and room to run.

The Vikings running back's average of 1.6 yards per carry at Tennessee on Sunday was his worst mark since he was 24 years old and taking handoffs from Brett Favre in 2009. Issues varied, coaches and players said, though offensive linemen shouldered the blame Thursday, four days after five of Peterson's 19 runs ended in negative yardage.

"Adrian's a great running back, but he can't run the ball if somebody's hitting you in the backfield," Vikings right tackle Andre Smith said. "No matter who you are."

A 31-yard outing against the Titans continued a stretch of underwhelming season openers for Peterson, which Vikings offensive coordinator Norv Turner noted when saying he expects Peterson to find his stride with time in the offense.

Turner stood by the coaching staff's decision to not play Peterson in the preseason. After reviewing Sunday's game, Peterson said he noticed a few runs in which he made the wrong decision.

"There were still four, five plays that I missed," Peterson said, "that [could've been] 50-, 60-yard plays, 20-yard plays. And vice versa, things that, offensively, guys came to the sideline and said, 'Hey, we're going to do better, we have to do better as a group.' "

Bradford leads huddle

Vikings coach Mike Zimmer reiterated Thursday that he will not name a starting quarterback before Sunday night.

Sam Bradford and Shaun Hill rotated throws during various quarterback drills, though it was Bradford who joined the starters just as team sessions began while media were ushered away from the practice field.

"I think he's a lot more comfortable," guard Alex Boone said of Bradford. "He's picking up the offense really well. He's in our [offensive line] room a lot, which is always good for a quarterback to do. His confidence level is through the roof right now."

The most difficult part of getting Bradford ready to start 15 days after trading for him, Turner said, is the rapport building between quarterback and his receivers.

"That's what we're trying to create in a short period of time," Turner said.

Still out

Three Vikings starters remained sidelined during practice: left tackle Matt Kalil, cornerback Xavier Rhodes and defensive tackle Sharrif Floyd.

While Kalil (hip) has dealt with a handful of injuries in his five-year NFL career, he has yet to miss a start.

Rhodes (right knee) and Floyd (left knee) wore braces as they watched from the sideline. Neither has practiced this week.

The only change to the injury report Thursday was running back Jerick McKinnon (foot/lower leg) being elevated to a full participant after he was limited on Wednesday.

Bridgewater visits practice

Teddy Bridgewater visited Vikings practice exactly one week after the 23-year-old quarterback underwent surgery to repair multiple torn ligaments.

Bridgewater was seen at the start of practice, escorted by his adviser and former NFL player Abram Elam, who helped him out of the back seat of a vehicle. Bridge­water's left knee was supported by a full leg brace.

"He's good, laughing and joking around," Zimmer said. "There was a bunch of guys in the training room when I went in there."

Last week at the Carrell Clinic in Dallas, Dr. Dan Cooper repaired Bridgewater's anterior cruciate ligament and other undisclosed damage done by a left knee dislocation suffered Aug. 30.