Last week the Vikings declined to renew the contract of offensive line coach Jeff Davidson, and quickly signed former Miami Dolphins Head Coach Tony Sporano as his replacement. Many are excited for the shakeup in hopes that Sporano will be able to help one of the leagues worst pass blocking units over the last two years. Others insist that injuries and Norv Turner's scheme were the main factors in our OL's poor performance. I decided to take a look at the recent performance of each in a few key areas.

Sack %

Sack % is simply the frequency a QB is sacked per drop back. I was able to find data going back to 2003. I excluded the 2003, 2004, and 2014 seasons for Sporano since he was serving as a TEs coach at the time.

Typically a sack % of around 5% is good for a top 10 finish, while anything over 7% is bottom 10. All three coaches have struggled in this metric fairly consistently.

Sporano has the highest average sack % since 2003, at 7.73%, which would have been good for 26th in the league in 2015. Davidson hasn't faired much better, with an average sack % of 7.35%. Turner is the best of the three, but his average of 6.54% is still well below league average and would have ranked 23rd in the league in 2015.

Most alarming in these numbers is the recent trends. Turner's average sack % jumps all the way to 7.46% over the last 5 seasons. Sporano has finished with a sack % of 7.98% or higher in 3 of his last 4 seasons as an OL coach or OC, and in 2 of those seasons his units finished dead last in the league.

Rush Y.P.C.

Another common metric used to evaluate OL play is a team's success running the football. Instead of looking at total rushing yards, I decided to look at yards per carry as I feel it gives a better picture of a teams success running the ball. Again I went back to 2003 and excluded Sporano's years as a TEs coach.

Davidson leads the group with an average Y.P.C. of 4.40, but benefited from having Peterson, DeAngelo Williams, and Jonathan Stewart as his lead backs for the past 9 seasons. Turner and Sporano both finished with a respectable 4.05, which is right around league average, but have also had the benefit of working with some great backs over this time.

PFF Rank

The last metric I looked at was Pro Football Focuses offensive line rankings. For anyone who's not familiar with PFF, the essentially attempt to quantify the eye test, assigning each player on the field a grade for each play. So if, for example, a QB holds the ball for 4 or 5 seconds before taking a sack, it would look bad for the OL in sack % stats, but would probably garner a positive grade from PFF as the offensive line kept the defenders at bay for a relatively long time. PFF rankings go back to 2009, and the 2015 rankings have not yet been released, so they aren't included.

This chart is a little strange to look at, as the lower the finish the better. For example in 2009, Sporano's Dolphins finished 2nd, Davidson's Panthers finished 15th, and Turner's Chargers finished 21st.

Davidson comes out on top of this measure as well, with an average rank of 10.8. Sporano also fairs well here, with an average rank of 13.33. Turner's groups are ranked at 20.5 on average.

So based on these metrics, I don't expect our OL performance to change a whole lot unless we get a large influx of talent. Sporano, like Turner and Davidson, has had success running the ball but struggled with pass protection, so Teddy may very well be under siege again in 2016. One reason for optimism is that Sporano and Turner have used the same power man blocking scheme for most of their careers, where Davidson up until 2014 had primarily taught zone blocking. Perhaps with the OL coach and the OC on the same page in terms of technique, we will see a more cohesive unit.





