See more of the story

NFL free agency begins next week, starting with the negotiating window on Monday and the opening bell for the 2018 league year at 3 p.m. Wednesday. Here's the fourth of a series assessing the Vikings' top five needs and how they could address them in free agency.

No. 5: Linebacker
No. 4: Tight end
No. 3: Defensive tackle

Need No. 2: Offensive line

The position was the Vikings' biggest need a year ago, when they gave a combined $36.8 million in guaranteed money to tackles Riley Reiff and Mike Remmers, before using a third-round pick on center Pat Elflein. And while the Vikings line improved in 2017, it still needs another round of resources this spring. Word at the NFL combine was the Vikings could consider moving Remmers to guard full-time in 2018; whether they do that or sign another player, they'll need to find a starter at right guard with Joe Berger hitting free agency. The group also needs more depth, especially given the fact jeremiah Sirles could leave in free agency.

Pending free agents: G Joe Berger (made $3.5 million over last 2 seasons), G Jeremiah Sirles (made $690,000 last season; Vikings do not plan to give Sirles restricted free agent qualifying offer), G Nick Easton (made $615,000 last season; RFA this spring).

Current roster: T Riley Reiff ($11.4 million cap hit in 2018), Remmers ($4.6 million), Elflein ($871,210), G Josh Andrews ($680,000), T Rashod Hill ($630,000), G Danny Isidora ($605,487), T Aviante Collins ($560,000), C Cornelius Edison ($555,000), T Dieugot Joseph ($555,000), T Storm Norton ($480,000).

Current money invested: $20.3 million, 28th-most among NFL offensive lines, according to OverTheCap.com.

Top free agents available:

T Cameron Fleming (Patriots) — He started six regular-season games for the Patriots and was the team's right tackle in the AFC Championship Game and Super Bowl. Fleming made only $1.8 million as a restricted free agent last year, and might be a sensible pickup for the Vikings, particularly if they're thinking of playing Remmers at guard and trying to find a tackle.

T Nate Solder (Patriots) — He might be the top left tackle on the market, which means he'll make more money than the Vikings would likely be willing to pay for offensive line help.

G Andrew Norwell (Panthers) — The 26-year-old is probably the top guard on the market, though reports have him likely headed to the Giants to reunite with former Carolina general manager Dave Gettelman, If he doesn't end up in New York, and the Vikings wanted to spend some significant money on a guard, they could leave Remmers at tackle and reunite him with his old teammate.

T Justin Pugh (Giants) — A back injury limited Pugh to eight games in 2017, but he's played both guard and tackle, and could add some versatility to the Vikings' line. Pugh started two games at left guard for the Giants last year, but he spent most of his time at right tackle.

G Josh Kline (Titans) — Kline didn't miss a snap for the Titans in 2017, after playing all but two snaps in 2016. He's made steady progress as a pass protector, allowing only two sacks without any additional hits on the quarterback in 2017, according to Pro Football Focus.

G Josh Sitton (Bears) — Would the Vikings think about signing the 31-year-old after facing him for 10 years with the Packers and Bears? They might want to take a look, after Sitton played 13 games and had another strong year in Chicago. He's made four Pro Bowls since 2012, and while injuries are a concern with him, he's versatile and plays with an edge. The Vikings would have to determine if he's still mobile enough to do everything they'd like from their guards in their zone blocking scheme.

Also keep an eye on: Greg Robinson (Lions), Evan Smith (Buccaneers), D.J. Fluker (Giants)