The mood at Winter Park reflects the Vikings record. Confident, relaxed, plenty of smiles. A 5-0 start and being the NFL's lone remaining undefeated team has that effect.

The Vikings know they're good, but they're not content. They're not just winning, they're dominating opponents. The chemistry inside the locker room seems unified by a common purpose.

One need not guzzle purple Kool-Aid to suggest the Vikings belong on the short list of teams that can stake claim to being the best in the NFL right now. They deserve all the praise being heaped upon them.

And yet, at the expense of sounding like Debbie Downer, two areas create nagging uneasiness amid the euphoria. The offensive line and Blair Walsh remain big, bold question marks that could derail the happy train.

The Vikings remain perfect despite injuries and inconsistency with their line and placekicker. That's a credit to the coaching staff and collective performance of the entire roster. That's also tempting fate if it continues without marked improvement.

The offensive line has been a battered mess from the start. How often does a team lose both starting tackles (Matt Kalil and Andre Smith) and No. 1 backup (Mike Harris, undisclosed medical condition) to injured reserve in the first five weeks?

Emergency left tackle T.J. Clemmings likely set off alarm bells internally after whiffing three times against Houston Texans pass rushers. The team needed help at tackle and signed veteran Jake Long off the street during the bye.

Clemmings has become an easy target for criticism, but left tackle is new to him. He had an uneven rookie season at right tackle and now he's being asked to protect Sam Bradford's blind side? That's dangerous.

Bradford's career revival has put him in early-season MVP conversation. The fact he's done so behind patchwork protection makes his performance even more impressive. But he won't survive if his line allows defenders to take free runs at him.

Long's arrival could initiate more shuffling. Here's one guess: Long starts at left tackle soon (perhaps Sunday at Philadelphia), Clemmings moves back to the right side and Jeremiah Sirles returns to his utility role. That would allow Sirles to fill in at multiple positions if inconsistency continues or more injuries occur.

"They've definitely gone through some adversity," said Long, who indicated he's ready to play this week if needed. "They've done a good job of sticking together."

Injuries can't be predicted, and certainly not to this extent, but the issues should compel General Manager Rick Spielman to re-think his draft strategy.

Spielman has stocked the roster with young talent and created depth across the board. But offensive line hasn't been a high draft priority under his watch.

The Vikings have selected an offensive lineman in the first three rounds only twice since 2007 — Phil Loadholt (second round, 2009) and Kalil (first round, 2012).

Spielman moved to bolster the line this offseason by signing free agents Alex Boone and Smith. Injuries forced him to sign Long.

Viable options will be scarce if they encounter more attrition the final 11 weeks.

Spielman will face another problem if Walsh misses a few more kicks. At what point will the organization reach its breaking point?

Walsh has missed three field goals and two extra points in five games, though he had a clean outing against the Texans.

In his annual bye week conversation with beat writers, Spielman noted that he has been patient with young players but that he will "monitor" Walsh's performance.

"We don't have any plans of bringing in a kicker at this point," he said.

The Vikings seem content, for now, to hope that Walsh regains his form and doesn't cost them a game. That's definitely a gamble based on his final kick last season and his misses this season.

Time will tell if their show of faith will be proven right, or painfully wrong. The answer probably won't become clear until he's asked to make a pressure kick in the postseason.

For now, uneasiness over Walsh and a beat-up offensive line is just that — uneasiness in a perfect start. That hasn't cost the Vikings but it's also not something to dismiss.

Chip Scoggins chip.scoggins@startribune.com