Blair Walsh is struggling. This isn't a new thing, but now that he's 2-for-6 in the preseason on field goal attempts and missed one of those expanded 33-yard extra points against the Raiders the other night, it's officially a concern of Mike Zimmer and the rest of the Vikings staff. Walsh was also the league's least-accurate kicker last season (74.3 percent), but the Vikings showed faith in him this past offseason by signing him to a long-term contract.

What's going on with Walsh? Let's take a closer look at his struggles:

THEORY ONE: Kicking outdoors is messing with him. For the first two years of his pro career (2012 and 2013), Walsh's home field was the friendly confines of the Metrodome. Knowing your kicking conditions will be the same no matter what is a nice feeling, and Walsh capitalized: He didn't miss a single field goal in the Dome as a rookie in 2012 and missed just two in 2013 — a 57-yarder and a 55-yarder, both excusable misses.

Last season, with his home field moved outside, Walsh missed four field goals at TCF Bank Stadium. He actually was MORE accurate outside than inside last year (21 for 27 outside, 77.8 percent and 5 for 8 inside, 62.5 percent), but the three inside misses were all in one game in Detroit. One was a 53-yarder; one was a 26-yarder that was blocked; and the last was a ridiculous 68-yarder.

For his career, Walsh is an 88.4 percent kicker inside domes and retractable roof stadiums, whereas he is 80.4 percent outside. This dichotomy is not just isolated to Walsh; a Harvard Sports Analysis study in 2009 concluded, not surprisingly, that "there is a strong association between kicking indoors and greater FG success." And for 2014 and 2015, Walsh has eight more guaranteed games outside than he did in 2012 and 2013.

Some kickers, of course, are good no matter what. But if you're used to a Dome, kicking outside — wind, damp field, etc. — can be a challenge. Greg Zuerlein of the Rams, who has had his home games in a dome for the past three seasons, is an 88.7 percent kicker in domes and a 71.0 percent kicker outside in that span.

The bad news if this theory is solid — and it appears there is a decent amount of merit to it — is that Walsh has to kick outside again this year (his rough preseason game the other night, of course, was in TCF Bank Stadium). The good news is that this is only temporary and he will be back kicking inside next year at the new Vikings stadium.

THEORY TWO: Walsh is just flat-out streaky, going back to his college days at Georgia. He was 15-for-23 on field goals as a freshman (65 percent), then a combined 40 for 45 as a sophomore and junior before slumping to just 21 for 35 (60 percent) as a senior. Kickers go through funks. Maybe that's all it is?

THEORY THREE: A new holder in 2013 and inconsistencies with the snapper/holder/kicker progression have hurt Walsh. Walsh's best year as a pro by far came in 2012 as a rookie and with former P Chris Kluwe holding (remember, he only missed three FGs all year and was a perfect 10 for 10 from 50 yards or more).

That said, after Kluwe was replaced as punter and holder by Jeff Locke in 2013, Walsh still had a respectable season: 26 for 30 on field goals, with three of the four misses coming from 50 or more. Locke, though, has been the holder in times of struggle (2014 and this preseason) as well.

What about the snapper? After all, the Vikings did just release longtime long snapper Cullen Loeffler in favor of Kevin McDermott. You don't change that up if it's working. Zimmer on Monday talked about Loeffler, offering a mixed bag in regards to his snaps this preseason: "A couple of them were high. There was about two of them on the two extra points, the two field goals, were a little high, but they were manageable for sure. No, releasing Cullen Loeffler had nothing to do with what happened the other night. It's a process of what happened during training camp this whole time."

As for why the move was made now, Zimmer said: "Basically it was to get the timing down between the center, holder and the kicker and the punter."

In short: Loeffler wasn't perfect, but that doesn't let the rest of the chain of command (Locke and Walsh) off the hook for a bad night. And it should be noted that Loeffler was the snapper when Walsh was at his best, too.

THEORY FOUR: His confidence is down, and it's affecting his mechanics. Of Walsh's missed kicks the other night, Zimmer said, "it looked like he rushed one," though he couldn't identify a common thread between all the misses.

That said, rushing kicks was identified as a problem for Walsh coming out of college and was attributed to his senior year struggles. This is from a Star Tribune story in the 2012 preseason:

Despite leaving Georgia as the SEC's all-time leading scorer, Walsh had to climb out of a noticeable mental funk. "There wasn't a specific point or a game last year where I felt my confidence dip," he said. "It just wasn't right all year. And I just couldn't get my form back." Throughout the predraft process, Walsh regained his swagger. And since being drafted, he has invested endless time with special teams coach Mike Priefer cleaning up his mechanics.
Priefer asked Walsh to slow down his approach, feeling as if the rookie rushed too many kicks in 2011, often not allowing his holder to get the ball down in the right spot with an ideal tilt. "You need that rhythm with the snap, the hold and the kick," said Chris Kluwe, the Vikings' punter and holder on kicks. "And I think slowing Blair down just that tenth- or two-tenths of a second has made a difference. He doesn't feel like he's hurrying coming through the ball."

It seems entirely plausible that rushing is again hurting Walsh. The temptation when you struggle at anything is to press, which is the opposite of what you should do.

BEST GUESS: Kicking outside, particularly in a stadium noted for tricky winds like TCF Bank, has impacted some of Walsh's kicks directly (by pushing them around) and indirectly (by playing with his head). But he says he feels as though he's kicked well in training sessions, an assessment corroborated by our own Matt Vensel.

In the long term, returning inside for home games next year should cure a lot of Walsh's ills. When you feel confident, mechanics seem to fall into place.

In the short term, Walsh and the Vikings need to hope that the kicking game rounds into shape in 2015 — and does not derail what in many ways looks to be a promising season.