EDEN PRAIRIE, Minn. –There's no denying that Minnesota's offensive line sustained a crippling number of injuries during the 2016 season, but Vikings General Manager Rick Spielman said there's no room for excuses, only for improvements.

The Vikings lost two of their starting linemen – Matt Kalil and Andre Smith – to injuries for almost the entire season and had a number of other players miss stints of time throughout the year.

"I could sit here and say I ran out of fingers and toes trying to plug the dam, but that's not an excuse," Spielman said in an interview with Vikings.com's Mike Wobschall. "The end result is we were 8-8, and we need to get better; 8-8 is not acceptable."

Added Spielman: "I know everybody in this building is working extremely hard to make sure that we can improve on that going forward into [the 2017 season]."

Over 16 games of 2016, the Vikings used eight different starting combinations on the offensive line.

Spielman and his staff thought they were sitting in a pretty good position at a similar time last year, when they signed Smith and Alex Boone as free agents while also planning on the healthy return of Phil Loadholt – who retired in July – and Kalil.

Several linemen not originally slated to start ended up filling in during the season – ultimately leading to 12 players seeing action on the line at one point or another.

"A lot of times, backups are able to get you through three, four, five games without getting exposed," Spielman told Twin Cities media members last week. "But if you have to play them for 14, 16 games' exposure, they may not be able to match up every week."

According to Spielman, there's a silver lining to the patchwork line relied on throughout 2016: he and the coaching staff now have a clearer idea of players' abilities on game day rather than relying solely on training camp, practice or preseason.

The Vikings got good looks at Nick Easton and Zac Kerin when their numbers were called, they picked up on clear strengths and weaknesses from T.J. Clemmings when he was moved from right to left tackle, and they saw things they liked in Rashod Hill, a late-season add from the Jaguars practice squad. Spielman pointed out that Clemmings was tasked with playing left tackle for the first time.

"We have a better feel of these backup offensive linemen because they all had to play," Spielman said. "What is their ceiling?" Spielman said. "Are they going to ascend? Do we think we can win with these guys?

"Knowing what we know about our young backups right now, it will help as we make decisions going forward on the areas we need to address," he added.

The disruptions on the offensive line prominently placed the position group in Spielman's pre-combine media session with writers last week.

Like all positions on Minnesota's roster, the offensive line is assessed using the general manager's **specific color-coding system**, ranking players from blue (Pro Bowl caliber) to red (16-game starter) to purple (special teams contributor; capable of starting a few games).

"Most of the guys that become successful are going to get drafted early on," Spielman said. "Seventy-nine percent of offensive linemen that start two or more seasons that play at a red or blue level are going to be good players for you."

Spielman added that he often gets asked why he hasn't picked more offensive linemen early in the draft.

"Depending on where you're picking, maybe the offensive linemen weren't available to you by the time you picked," Spielman said. "But I also know that we've made some significant first-round picks that are impact players on our roster."

Kalil was a first-round pick in 2012, and Loadholt was a second-rounder in 2009, but most linemen have been later-round selections or acquired through trades.

Spielman also has studied how long it takes offensive linemen to develop after entering the NFL. He referenced Patriots tackle Marcus Cannon, a sixth-year player who last season started 15 games for the first time in his career.

"We've looked at him through his whole career, just like we assess every player in the NFL, and usually years four to five is when, if those guys are good enough, those are the years they start to come in and be red to red-minus type starters," Spielman said. "There's different ways that I've had to look back and see, 'What are we doing right or wrong with this offensive line, and how do we get it addressed?'

"That was the whole focal point on a lot of the studies and a lot of the analytics that I've been doing since the end of the season," Spielman added. "So now I know specifically what we may try to do in free agency or what we may try to do in the draft."