In the NFL, the offensive line is a position, like many, where once a player turns 30, they get phased out. The Arizona Cardinals have an offensive line where the starters are almost 30 years old on average.

Because of how the line is constructed -- built mostly in free agency, the Cardinals have the third oldest starting offensive line in the NFL, averaging 29.3 years old, according to a blog post on SB Nation Dallas Cowboys site Blogging the Boys.

That number will possibly go down. Right now, the Cardinals line from left to right is left tackle Jared Veldheer (28 years old), left guard Mike Iupati (29 years old), center A.Q. Shipley (29 years old), right guard Evan Mathis (34 years old) and right tackle D.J. Humphries (22 years old).

This number could go down some. Fourth round pick Evan Boehm, who is 22, is expected to battle for the starting center position.

As it stands, the line consists of four free agent signings and one draft pick. Humphries is the one guy they drafted.

With an older line, there are some benefits -- they are experienced. That experience is helpful because they are protecting a 36-year old Carson Palmer. Of course, older players, especially when you have added them as free agents, are more expensive.

Veldheer makes $7.25 million this season. Iupati makes $4.5 million. Shipley makes less than $1 million. Mathis will make $4 million if he plays all season. Humphries makes about $840,000.

An older line can be concerning, too. It gets old. Players begin to decline in their play.

As of now, the Cardinals line is ideal -- they have very good veterans, a stopgap in Shipley and Humphries ready to be the guy at right tackle. Then Boehm is there trying to crack the lineup.

Would you construct the line any differently? Is the age of the line a concern for you?