Summary: Poppinga was signed after the Cowboys lost Bruce Carter for the season to a broken elbow. He worked out for the Cowboys earlier in the season but the team chose to sign Gary Guyton, who lasted last than week. Poppinga played in four games with one start and had four tackles. He also had four tackles on special teams. He played mostly inside linebacker but also worked on the outside when the Cowboys went with a hybrid 4-3 look.
Why keep him: He has some position flexibility and can play special teams, and he would command only a one-year deal at or near the minimum. While a tad eccentric, he brings energy to the practice field.
Why let him go: With a 4-3 scheme, the Cowboys need to get faster at linebacker. Poppinga turns 34 in September.
Best guess: He was a stop-gap player because of injury in 2012 and doesn't figure in the future plans.
Follow the rest of the series here.