Minnesota Vikings: Just How Much Does Donovan McNabb Have Left?

Minnesota Vikings head coach Leslie Frazier and offensive coordinator Bill Musgrave are looking to Donovan McNabb to carry the reins of leadership for the Vikings offense until they feel first-round draft pick Christian Ponder is NFL-ready.

From the beginning, I have not been in favor of the Vikings signing of yet another late-in-his-career quarterback to come in as a stopgap as the Vikings coaches attempt to find that franchise quarterback.

It's nothing against McNabb—it's the approach the Vikings have taken for almost 20 years I loathe.

Other than Daunte Culpepper from 2000 to 2004, the Vikings have not drafted a player that has started as their No. 1 quarterback for more than two consecutive seasons. 

The last to do this was Rich Gannon who started from 1990 to 1992—that's 18 seasons with the likes of Jim McMahon, Warren Moon, Randall Cunningham, Gus Frerotte and Brett Favre at quarterback. Over that time, the Vikings have not made a trip to the Super Bowl.

McNabb, who has played 11 seasons in the NFL, will turn 35 in Week 12 of the season. Whether or not he plays beyond the one-year contract he signed with the Vikings will depend on the play of the patched-up offensive line, the development of Christian Ponder and the effectiveness he has to lead the Vikings to touchdowns—something he did only once in the preseason. 

McNabb has indicated he would like to play for several more years. In order for that to happen he needs to play a lot better than he did in Washington last season when he was benched in favor of Rex Grossman.

In 13 starts for Washington, McNabb had a 77.1 passer rating—the lowest since his rookie season in 1999. Another concern with McNabb may be that he has started all 16 games in a season only four times in his career, the last being in 2008.

How long can McNabb play in the NFL and how effective should we expect him to be?

In an attempt to find some answers I compiled the statistics of the top 35 quarterbacks in NFL history in passing attempts who played beyond their 34th birthday, and found some interesting facts.

Performance Tends To Drop with Time

For only 13 of the 35 quarterbacks did their passer rating after turning 34 exceed that of their career. The improvement averaged 5.8 percent with Oakland quarterback Jim Plunkett making the biggest jump, improving by 13.3 percent, with a passer rating of 76.5 after 34 compared to 67.5 for his career.

That means the majority of quarterbacks, 22 of 35 to be exact, actually saw their performance drop as their careers continued. Their combined passer rating dropped an average of 6.2 percent.

Johnny Unitas had one of the largest declines at 14.3 percent.

Projecting the average drop to Donovan McNabb's 85.7 career passer rating, he should finish the season somewhere with a passer rating of 80—while an improvement over Brett Favre's 69.9 rating for the Vikings last season, it's only a slight improvement over the 77.1 passer rating McNabb had for the Redskins.

Last season McNabb completed 275-of-472 passes for 3,377 yards with 14 touchdowns and 15 interceptions. In order to improve that to a passer rating of 80, he would have to throw two more touchdowns and one fewer interception. 

Quarterbacks over 34 Tend To Win More Than They Lose

The combined record of the 35 quarterbacks who played beyond the age of 34 is 992-834, a .543 winning percentage.

Joe Montana, who has a .713 career winning percentage, led the list with a 31-9 over the last four years of his career—an incredible .775 winning percentage.

For Donovan McNabb, who owns a .626 career winning percentage, this means if he can play all 16 games this season for the Vikings, they should finish with between eight and 10 victories this season.

If McNabb misses a game, for any reason, there is no way this team does any better than 8-8.

Playoffs Are Hard To Come by for Quarterbacks 34 and Older

The combined number of seasons played by the list of quarterbacks over the age of 34 added up to 198. Only 61 of them, or 30.8 percent, resulted in the quarterback leading his team into the playoffs. 

Warren Moon, who didn't start his NFL career until the age of 28, had the most playoff appearances after turning 34 with six.

Fran Tarkenton was next with five playoff appearances followed by Dan Marino, Joe Montana and Steve Young, who were able to accomplish this four times each. 

The track records of these quarterbacks indicate that being successful early in your career will make for more success later.

For Donovan McNabb, who has led his team to the playoffs in seven of 11 seasons, the odds are better that he can do it over the next three to five seasons. 

The Minnesota Vikings boast some pretty explosive offensive weapons with Adrian Peterson and Percy Harvin. If the offensive line can keep McNabb on his feet, I estimate about a 50 percent chance of the Vikings making the playoffs, most likely as a wild-card team.

As mentioned on the previous slide, this means McNabb needs to play the entire season and lead the Vikings to a 10-6 record. However, with a new coaching staff and a new offensive scheme it's more likely the Vikings finish 8-8, and out of the playoffs.

The Top QBs in Pass Attempts Retired Close to 40

In order to identify 35 quarterbacks who played beyond the age of 34, I had to dig pretty deep down the career list of quarterbacks with the most pass attempts. I ended up going to No. 55, Jeff Garcia (I included Jim McMahon who played one season for Minnesota, and is No. 101 on the list).

I chose this stat because is has a greater significance than the number of games played—each time a quarterback drops back to pass it could be the last play in his career.

The number of years a quarterback played after turning 34 ranged from three to 11—the latter being matched Warren Moon and Vinny Testaverde, with the average being 5.6 years.

This means with Donovan McNabb entering the season at the age of 34 he could be expected to play until he is 39.6 years old, or into the 2016 season.

So What Does This All Mean?

Donovan McNabb has had a very successful career with some very good Philadelphia Eagles teams, many that could be considered better than the Vikings squad of 2011. 

Don't expect much of a turnaround from the 6-10 record of last season.

This is not just my opinion; many lines in Las Vegas list the odds of the Vikings winning Super Bowl at 60:1, the lowest in the NFC North—even the Lions are listed higher at 40:1.

How much does McNabb have left? That will really depend on his ability to avoid the pass rush, because the pass protection will not be any better this season than last.

There's a reason Minnesota only signed McNabb to a one-year contract, and that's because they don't expect him to be the starter next season. If McNabb plays next season it will be for his fourth team in as many years. That does not bode well for his career lasting more than a couple seasons at most.