What is the biggest driver of the Blue Jays' success this season? A question on many Blue Jays fans' minds is whether the success of this team is rooted in positive regression from the core group, such as the drivers like Vladdy, Bo, and George and Kirk, for example. Or, does it come down to the unexpected contributors such as Heineman, Straw, Clement, and more? What is biggest driver of Blue Jays success this season? The unexpected contributors have raised the floor, but positive regression has raised the ceiling.