Summary: Dockery was signed in training camp after injuries to the interior offensive line left the Cowboys thin. Dockery started one game and was a reliable veteran backup. When Mackenzy Bernadeau struggled, offensive line coach Bill Callahan gave Dockery first-team reps in practice. Bernadeau would improve and he maintained his starting role, but having Dockery around was good insurance for the Cowboys. He practiced through a bursa sac above his knee in the last two months of the season.
Why keep him: Nothing wrong with keeping veteran linemen around in case younger linemen don't develop. Dockery is one of those trusted veterans who can adapt to both guard spots and can mentor young linemen.
Why let him go: It's probably time to let the 32-year old test the free agent market again. The Cowboys have young interior linemen in Kevin Kowalski, Phil Costa, David Arkin and Ronald Leary, who will be given a chance to make the 53-man roster.
Best guess: Dockery is good for the short term and was needed in 2012 when injuries and ineffective play hampered the offensive line. He most likely will hit the free agent market again, so it's time for the Cowboys to let him go and rely on younger linemen.