– Just because the Vikings offensive line exhibited a welcomed resurgence last season doesn't mean General Manager Rick Spielman has turned his attention elsewhere. The unit now faces a few questions, so line coach Tony Sparano and the Vikings' personnel department have been busy poking and prodding prospective linemen at the NFL scouting combine in Indianapolis.

"You have to always keep investing in that offensive and defensive line," Spielman said, "with the style we play, the philosophy coach [Mike] Zimmer wants to play."

Last season's improvement centered on the additions of free-agent left tackle Riley Reiff and rookie center Pat Elflein. The Vikings also signed Mike Remmers to play right tackle, but he finished the year playing guard in the final three games.

Whether the Vikings draft a tackle or guard — potentially with pick No. 30 — could determine what position Remmers plays in 2018, according to Zimmer. There might be an opening at right guard, with Joe Berger set to hit free agency, too.

"It gives us more options," Zimmer said. "If we find a tackle in the draft or if we find a guard in the draft," it could determine Remmers' position. It's worth noting Vikings coaches chose to play Rashod Hill over Remmers at right tackle in both playoff games.

The Vikings could again go the free-agent route — Dolphins right tackle Ja'Wuan James could be available — or turn to the draft's intriguing early-round options. Fortunately, this year's draft class is expected to bounce back from a 2017 group NFL draft analyst Mike Mayock called "the worst offensive line year ever."

"As far as interior, the top end of [2018] is really good," Mayock said. "Quenton Nelson will be gone early. The next group of guys: Isaiah Wynn, James Daniels, Will Hernandez, Billy Price, I think they'll all probably go, worst case, by the end of the second, beginning of the third [round]."

For possible guards, there's also Arkansas' Frank Ragnow.

Ragnow, who required ankle surgery last fall, is a Chanhassen product. He finished his Razorbacks career as a center following 13 starts at right guard. The oldest boy of five Ragnow siblings said he grew up a Vikings fan, so it'd be "surreal" if he was drafted by his hometown team.

"I'd probably live with my mom for a while, and it would be awesome," Ragnow said. "I'm a Minnesota boy, and I take a lot of pride in that state."

The Vikings are interested. They were Ragnow's first meeting with NFL teams this week, he said.

The Vikings also met with Ohio State center/guard Billy Price. Price caught a tough break when he partially tore a pectoral muscle during the bench press Thursday. He doesn't expect he'll need surgery, but depending on his recovery timetable the injury could hurt his draft stock.

Elflein, recovering from a couple offseason operations, including ankle surgery, reached out to his former Buckeye teammate this week.

"He was one of the first guys to text me," Price said. "'Hey, man, I heard about this; what's going on?' He's been a huge help during this entire process, just because of the fact that, 'Hey Pat, what do I expect? How does your body feel during the season?' "

The draft's tackle prospects are led by Notre Dame's Mike McGlinchey, the first cousin of NFL MVP quarterback Matt Ryan, Texas' Connor Williams, UCLA's Kolton Miller and Oregon's Tyrell Crosby.

One massive (6-8, 360 pounds) prospect, Oklahoma tackle Orlando Brown, didn't help his cause during Friday's on-field workouts. Brown put up lineman-low numbers in the bench press (14 reps) and 40-yard dash (5.85 seconds).

Outside of McGlinchey and Williams, according to former NFL scout Dan Hatman, the tackle class is largely a group of unrefined athletes. That includes Miller, the 6-foot-9 Bruins tackle who was a standout in the 40-yard dash, broad and vertical jumps.

"You just have to figure out that raw lump of clay and figure out: Can he do it?" Hatman said. "Does he want to do it? Not technicians of their craft."

Whoever the Vikings bring in should get plenty of work this spring. Left guard Nick Easton, a restricted free agent, and Elflein are coming off ankle surgeries. They're not expected to be ready until training camp.

"We'll continue to look and continue to try to invest [in the offensive line]," Spielman said.