I believe the context you are referring to would be referring to ability.
Dan Marino for example had flawless mechanics, and a great ability to throw the ball...however he was not as athletic as say a guy like Randall Cunningham. Randall Cunningham didn't have the throwing ability of a Dan Marino, but he could make plays that most other QBs couldn't.
Steve Young was a very good blend of these two types of passers. He could make plays with both his throwing and/or running ability.
Athleticism without mechanics will not get a player very far (see: Daunte Culpepper)...however few players without athletic ability can use just mechanics to succeed (Manning has, but Grossman, Alex Smith, Pennington, Boller, Brian Griese and other have failed.)