Where did you hear/see this report? It seems that every time there's an intriguing udfa or middle-low draft choice, the reason they're not playing is because of their inability to learn the playbook.
Long ago we had a back named Wilmont Perry. He was tough and somewhat reminded you of Eddie George because of his style. The "rumor" why he didn't play or last is because he couldn't learn the playbook.
Well you have to be brainless if you couldn't learn Abramowicz's high school offense.