Bob Quinn knew it immediately after the Detroit Lions' season was over and probably figured it out during the season, too. He had to improve his team’s running game and to do that, he had to possibly make some changes on the offensive line.

And for the second straight season, the area he marked for the most improvement at the start of the offseason is where he followed through with important moves as offensive tackle Rick Wagner expects to sign with the Lions when free agency opens Thursday at 4 p.m. ET.

At the NFL combine last week, Quinn explained how the entire landscape of a position in an offseason -- and all of the positions between the draft and free agency -- could factor into what directions the team went in signing players.

Right tackle Rick Wagner should help boost the Lions' running game next season. Mitchell Layton/Getty Images

So it’s plausible that the dearth of talented tackles in free agency and the draft this year also helped push Detroit to go after Wagner, the No. 11 free agent in the ESPN Top 150 and the best offensive tackle on the market.

“It factors in, it does,” Quinn said. “You got to look at not only the perceived lack of depth on the offensive line in this year’s draft, I think there’s some guys in the middle rounds that might be a little bit undervalued that could rise in the process here over the next month or so.

“But we look at that. We look at who might be available next season under free agency. You got to look at everything.”

And that’s a smart long-view look for Quinn, who spent last season bulking up the middle class of his roster through free agency (and the draft) while signing the best receiver on the market in Marvin Jones. It was a free-agent group that worked out well for the most part, with Quinn fully acknowledging a team isn’t going to hit on every free agent.

At this time last year, after Calvin Johnson’s retirement, signing Jones was a good start and it was bolstered by moves after Jones. And that’s what Wagner is this offseason -- a good start at an obvious position of need with the best available player on the market. Based off of Quinn’s history -- admittedly a small one -- he could be on pace for another strong free-agency period.

That begins with Wagner, who is a strong pass-blocker and is good in the running game. He is the one player heading to free agency that appeared to be an upgrade from Riley Reiff, who will now be finding a new home after spending his first five years in Detroit.

The 27-year-old Wagner has been pretty durable during his career, too. He’s only missed two games in four years -- and started every game he was available for other than one over the past three seasons. A Lisfranc sprain at the end of the 2014 season could help explain some of the issues he had in 2015 -- the only year in his three years as a starter where he struggled.

His 2016 season, though, showed he could be a pretty strong right tackle when he wasn’t dealing with an injury, and that was enough to sign him.

Wagner also fits what the Lions look for in offensive linemen: athleticism.

Even at 6-foot-6, 310 pounds, he should have pretty good footwork. He was a high school tight end who actually walked on to the Wisconsin football team as a tight end instead of an offensive tackle. As a high school tight end, he had 39 catches for 900 yards and six touchdowns. He also played high school basketball, a sport many offensive linemen, including Lions left tackle Taylor Decker, have said helps with overall footwork.

While those things are in his long past at this point, they clearly helped him in the present as well, which is what is making him the Lions' right tackle of the future. And that’s a right tackle that the Lions are hoping will shore up their offensive line.