In the NFL it is a known fact that the left tackle is the most important position in protecting the quarterback.
While Vikings left tackle Matt Kalil started all 16 games last season, he noted at the end of the season that knee inflammation and swelling was serious enough that it required surgery in the offseason. Kalil's injuries, mixed with injuries to center John Sullivan and guard Charlie Johnson, meant that the offensive line simply wasn't as able to protect the quarterback as they were in 2012, when Christian Ponder started every game.
Besides the offensive line's faults last season, the defense blew five games in the final minutes, which also helped contribute to a 5-10-1 record. Yet, there was plenty of blame pointed at Ponder for not providing the amount of offense needed to overcome the deficiencies of the defense.
That lack of quarterback protection last year had a lot to do with the lack of scoring and the team's losing record, compared to 10-6 in 2012.
Last season, Ponder played nine games, but overall the Vikings allowed 44 sacks (which ranked 22nd in the NFL) and 84 quarterback hits (which ranked 19th).
Compare that to 2012, when the Vikings allowed just 32 sacks (11th in the NFL) and just 64 QB hits (fifth) and you can see why blaming most of the team's disappointing 2013 performance on Ponder doesn't get to the bottom of the issue.
In 2012, when Ponder started every game and took them to the playoffs, Kalil was named to the Pro Bowl and was one of the key pieces of a revamped offensive line that helped lead Adrian Peterson to the second-best rushing season in NFL history, gaining 2,097 yards.
But last year Kalil battled injuries, as did several offensive linemen like Sullivan, who was a Pro Football Writers' Association All-Pro in 2012, and the team struggled to win close games as Peterson's yards dropped off to 1,266 in 2013.