Vikings fans have spent plenty of energy in recent days consumed by the question of who the team's offensive coordinator will be in 2019.

It's an important question for a team that sputtered on that side of the ball down the stretch in 2018, costing the Vikings a chance to make the playoffs.

But the answer also won't matter much if the Vikings don't fix their offensive line. All the creative play-calling and concepts in the world can't consistently mask an inability to block effectively.

Looking back at the last seven seasons of Vikings offensive history – which also coincides with Rick Spielman's time since being promoted to general manager in January 2012 – there's a strong correlation between relative offensive success and the play of the offensive line. Let's take a quick look:

*2012 and 2013: The Vikings had above-average lines both seasons, according to Pro Football Focus rankings. In 2012, they were No. 16 in pass blocking and No. 3 in run blocking — the latter helping Adrian Peterson on the way to an MVP season and a playoff berth.

Tackles Matt Kalil and Phil Loadholt, guards Charlie Johnson and Brandon Fusco, plus center John Sullivan started all 16 games, and the Vikings ranked No. 14 in points scored with Christian Ponder at QB.

The last Vikings offensive coordinator to have a truly good offensive line, at least according to Pro Football Focus, was Bill Musgrave in 2013. The Vikings that season were rated No. 6 in pass blocking and No. 4 in run blocking by PFF.

Unfortunately, those lads up front — same five as 2012, who all started at least 15 games in 2013 — were pass blocking for the inglorious quarterback trio of Christian Ponder (nine starts), Matt Cassel (six) and one eye-gouging game from Josh Freeman.

With those QBs and the best line the team has had in a while, the Vikings managed to finish tied for No. 14 in points per game; the bigger problem during that 5-10-1 season that sealed both Musgrave and head coach Leslie Frazier's fate was a defense that allowed a league-worst 30 points per game.

*2014 and 2015: Injuries and neglect started to catch up to the Vikings. They ranked No. 12 in run blocking both seasons, but No. 23 and No. 28 in pass blocking, respectively, with Norv Turner as offensive coordinator.

Teddy Bridgewater masked some of the problems by making plays with his feet — he ranked No. 9 among NFL QBs in clutch-weighted expected points added on rushes in 2015 — but the Vikings that year were No. 31 in passing yards. They dropped to 20th and 16th in points per game in 2014 and 2015, respectively, even with a stout defense often supplying prime opportunities.

*2016-2018: The 2016 season was derailed by offensive line ineffectiveness and injuries, with the Vikings finishing No. 30 in both pass blocking and run blocking per PFF. The Vikings nosedived to No. 23 in points per game, while Turner resigned halfway through the year and was replaced by Pat Shurmur.

In 2017, the Vikings added Riley Reiff and Mike Remmers in free agency while drafting Pat Elflein in the third round. PFF had Minnesota at No. 17 in pass blocking and No. 13 in run blocking — acceptably average and a huge upgrade over 2016. They finished No. 10 in points scored and went 13-3.

And then in 2018, the line regressed. The Vikings were No. 27 in pass blocking and No. 25 in run blocking. John DeFilippo, who replaced Shurmur after Shurmur took the head job with the Giants, was fired after 13 games and replaced by Kevin Stefanski. Neither could crack the code of putting up points against top teams, and the Vikings finished No. 19 in points.

The Vikings are surely doing their due diligence on coordinator candidates. But barring an influx of offensive line talent and/or coached-up internal improvement between now and September, the choice will only matter so much.