The Vikings coaching staff and front office are in the process of fully evaluating their roster as they plan for the opening of free agency in March as well as April's NFL Draft. As General Manager Rick Spielman, head coach Leslie Frazier and their respective staffs put their heads together, the Access Vikings team is doing the same. We are in the middle of delivering snapshot evaluations of every position group. Today, we look at the offensive line.

OFFENSIVE LINE

Get excited: The Vikings offensive front stayed healthy in 2012 and wound up starting the same quintet for all 16 regular season games plus the playoff contest in Green Bay. The unit of Matt Kalil, Charlie Johnson, John Sullivan, Brandon Fusco and Phil Loadholt developed a strong chemistry as the season went on. And while Adrian Peterson is certainly capable of attaining excellence behind even the most mediocre of offensive lines, there's no doubt his 2,097-yard explosion in 2012 was catalyzed by the bruising run blocking of the guys up front.

The Vikings also surrendered 17 fewer sacks in 2012 than they did in 2011 – from 49 down to 32. And despite the occasional lapse, the line also limited its costly penalties.

Without question, Sullivan emerged as the leader while Kalil's immediate impact further validated the Vikings' choice to use the No. 4 pick in last year's draft on him.

Sullivan's rise has been a fun one to keep an eye on. Five years ago, the Vikings nabbed him in the sixth round and were not exactly banking on that pick paying long-term dividends. They feared he was too slow and a bit too small to be much more than a serviceable back-up. But they also saw enough intangibles that they figured Sullivan was an OK value pick.

Since then, with a superb combination of intelligence and drive, Sullivan has kept getting better. So much so that the Vikings gave him an eye-opening five-year, $25 million extension in December 2011. Sullivan rewarded the organization with his best season yet, emerging as a standout who even received seven All-Pro votes.

Kalil, meanwhile, was everything the Vikings dreamed he'd be and more in pass protection. And there's a genuine belief at Winter Park that, barring injury, the starting left tackle position won't have to be addressed again until the 2020s. That's some pretty solid comfort to have.

Keep an eye on: The right side of the line with Loadholt and Fusco.

Loadholt is set to become a free agent in March. So between now and then, the Vikings will have to weigh whether it's worth giving Loadholt the money he will command in a long-term extension versus whether there might be comparable right tackle options in free agency or the draft.

A draft sleeper to keep an eye on would be Ohio State's Reid Fragel, a converted tight end who has loads of potential and could be a great value pick in Round 3 if he's still on the board.

The Vikings also have to be honest about what they see in DeMarcus Love, a 2011 sixth-round pick who missed all of this season with a torn pectoral muscle and whose durability seems like it might be iffy at best. Love was inactive for all 16 games his rookie season in 2011.

So just how does General Manager Rick Spielman see Loadholt fitting into the future plans? Spielman called Loadholt "a true warrior type player" and stressed the value of retaining continuity up front.

"We'll go through the process in comparing him to the [other] right tackles out there," Spielman said. "I know we would love to have that unit together for a while, just because I think with the offensive line if you can get them playing together, and with how they played this year, to have that same group keep working together, especially at the age a lot of those guys are at, it really helps you solidify yourself up front."

At guard, the Fusco situation is an interesting one. The 24-year-old struggled enough in the season's second month that the Vikings wound up cutting his reps without taking his starting spot away. Fusco was put in a timeshare with Geoff Schwartz for nine games. But Schwartz never stood out or did enough to unseat Fusco as the starter. And when Fusco regained his confidence in December, he regained full control of that right guard spot.

"I need to get better with my techniques," Fusco said. "That's what hindered me when I struggled some. And a lot of it is getting that confidence back. Towards the end of the season, I had some pretty strong games. And I can hang my hat on that and use that for next season. But now I have to strengthen my techniques."

Reason for worry: If the Vikings' health up front was a significant reason for their 10-win surge, it also left open the question to how good the depth is there. Schwartz, as we mentioned, was OK but nothing special during his time on the field and is now set to become a free agent. It'll be interesting to see if the Vikings make a push to retain him or whether Schwartz will seek opportunity elsewhere where he'd have a better chance to start.

The other back-up linemen who were on the active roster at season's end were: guard/center Joe Berger and tackle Troy Kropog. Guard Tyler Holmes and tackle Kevin Murphy, meanwhile, were on the practice squad and signed to futures contracts the week after the playoff loss in Green Bay.

Berger will be a free agent again in March. And it's hard to know how dependable any of those other young guys could be if circumstances pushed them into a starting role. In other words, don't be surprised if there's turnover in the Vikings' o-line situation.