Age a concern for the Ravens' offensive line?

In an effort to eventually become younger and more athletic on the offensive line, the


drafted a pair of linemen in April’s

NFL draft

. But with the signing of veteran

Bobbie Williams

, now the frontrunner to start at left guard entering training camp, the Ravens could enter the season with one of the


’s oldest starting five.

Left tackle

Bryant McKinnie

turns 33 in September. Williams turns 36 in September, too. Center

Matt Birk

celebrates his 36th birthday later this month. Right guard

Marshal Yanda

turns 28 in September. Right tackle

Michael Oher

is 26. Tally those up and you get a combined age of 159. So should the Ravens be concerned?


senior writer John Clayton thinks so. In a well-researched piece published last week, Clayton wrote about what he calls “The Theory of 150.” Based on some research, Clayton has concluded that "once a starting line reaches the combined age total of 150 and has three to five starters in their 30s, prepare for drop-offs." He cited the 2007

Chicago Bears

, the 2008

Washington Redskins

and 2009

Dallas Cowboys

as examples.

You can


The genesis of the theory for Clayton was those 2007 Bears, who were coming off a

Super Bowl

loss to the

Indianapolis Colts

. Former Bears general manager

Jerry Angelo

told Clayton that he planned to keep his aging offensive line together -- it had a combined age of 159 -- because continuity would be key for his starting line.

The Bears gave up 43 sacks, averaged 3.1 yards per carry and did not qualify for the playoffs after finishing with a 7-9 record.

Five years later, the Ravens are in a similar situation. They return four of their five starters from last year, but the one they lost was a Pro Bowler in guard

Ben Grubbs

. The offensive line had an uneven 2011 season, perhaps partially due to the implementation of a new zone blocking scheme and also the fact that the Ravens couldn’t get their starting five on the field together in training camp due to injuries and the late signing of McKinnie.

But this year, if the starting five is established early and given an opportunity to gel, improved -- maybe essential -- chemistry might be developed during those hot afternoon practices out at the

Under Armour

Performance Center in Owings Mills.

The problem is that the offensive line is the team’s biggest question mark on offense entering training camp, with


, and the open competition to replace Grubbs at guard. Those factors could open the door for the two draft picks, guard/tackle

Kelechi Osemele

and center

Gino Gradkowski

, and second-year lineman

Jah Reid

, who could be in the mix at guard or right tackle.

That’s why we don’t know for sure right now who will make up the Ravens’ starting offensive line. But if it does end up being the 159-year-old quintet mentioned by Clayton, Clayton’s research suggests that unless the 30-somethings can stay healthy and the line takes advantage of that continuity, the line should experience a drop-off. That’s not what fans will want to hear after the Ravens pledged to improve the line this offseason.