play a big part
play a big part (in something)
To have an extremely important or fundamental role (in some resultant situation, action, event, outcome, etc.). There were a lot of reason why I quit, but having to work 10 hours a day played a big part. Punk rock played a big part in forming my aesthetic sensibilities. The rookie quarterback ended up playing a big part in the team's amazing comeback victory yesterday.
play a big part (in something)and play a large part (in something)
Fig. to serve as a major part of some situation or event. The incredible amount of duplicative paperwork played a large part in my decision to find employment elsewhere.