The Vikings selected eight offensive linemen in the first six years with Rick Spielman orchestrating their draft preparations. That number could increase next week as Spielman continues an attempt to bolster the team's interior line positions with depth and more competition.

Spielman, who enters his third draft as general manager with final say, satisfactorily secured the edges via the draft by taking right tackle Phil Loadholt in the second round in 2009 and left tackle Matt Kalil fourth overall in 2012. Both are young, well-compensated for several more years and provide strong anchors around which to build. Consistency is all that's needed now.

Center John Sullivan was a tremendous draft-day bargain, coming as a sixth-round draft pick in what was believed to be just a throwaway part of the Jared Allen trade in 2008. Sullivan isn't in danger of losing his starting job, but he has to prove that past leg injuries and an off year in 2013 aren't something to worry about.

Right guard Brandon Fusco was a sixth-rounder in 2011. He became a starter in 2012 and nearly got benched because of inconsistent play. He was better in 2013, but still needs to work on consistency while proving he's a long-term answer.

That leaves left guard as the only starting position that hasn't been filled through the draft. Charlie Johnson was signed as a free agent in 2011. After struggling as the starter at left tackle that first year, he slid inside to his more natural left guard spot and played better in 2012.

But after a big step back in 2013, the Vikings were content to let him shop his services in free agency before bringing him back on a modest two-year deal. Their indifference as to whether he might leave indicates Johnson may still have to fight for his job with Jeff Baca, a sixth-round draft pick a year ago, or possibly a 2014 draft pick.

On paper, it would appear the Vikings' offensive line is set. Johnson, who turns 30 on Friday, is the oldest player on a unit that has been together since Week 1 in 2012. But despite their continuity, the line regressed as a unit in 2013. New blood, particularly at guard, might be in order.

And that new blood is something Spielman is always mindful of when it comes to offensive linemen and the draft. Only once, in 2007, his first year running the Vikings' draft, did he not take an offensive lineman.

Here's a look at how he's done in that regard:

Hits: Kalil, Loadholt, Sullivan, Fusco (shaky, but we'll make him a hit considering he was a sixth-rounder).

Misses: G Chris DeGeare, fifth round, 2010; DeMarcus Love, sixth round, 2011.

To be determined: Baca.

Incomplete: Travis Bond, seventh round, 2013. He was signed off the team's practice squad by Carolina during his rookie season.

PROJECTED STARTERS: Kalil, Johnson, Sullivan, Fusco, Loadholt.

DON'T FORGET ABOUT: Baca. He looked raw as a sixth-round pick a year ago. Most of his rookie development at guard unfolded during closed practices, so we won't be able to judge him until training camp and the preseason. If he truly made progress, as the team has said, he may challenge Johnson at left guard.

LEVEL OF NEED: Moderate. There are bigger needs, particularly on defense. That's why the Vikings re-signed Johnson. They weren't enamored with his 2013 season, but considered him good enough to bring back so they weren't forced to reach for a guard in the

FIVE PROSPECTS TO REMEMBER: LSU redshirt-sophomore guard Trai Turner, Furman guard Dakota Dozier, Ohio State center Corey Linsley, Wisconsin guard Ryan Groy and former University of Miami and Cretin-Derham Hall tackle Seantrel Henderson. Henderson, once a top prospect, has taken a hard fall through the years and has admitted that marijuana use led to multiple suspensions at Miami. But he's still 6-8, 345 pounds. Someone will think they can fix him.

OUR BEST GUESS: The Vikings will take a guard, but no higher than the fourth round, unless they trade down from the No. 8 overall position and pick up another third-rounder.