Here is the min specs and the recommended specs to play Rocket League on a mac:
Minimum:
OS: MacOS X 10.8.5
Processor: Intel Core i5 2.4 GHz
Memory: 8 GB RAM
Graphics: OpenGL 4.1 - ATI Radeon HD 5670, NVIDIA GeForce GT 640M, Intel HD Graphics 4000 or Iris Pro Graphics
Network: Broadband Internet connection
Storage: 7 GB available space
Recommended:
OS: MacOS X 10.8.5 or Newer
Processor: Intel Core i7 2.4 GHz+
Memory: 8 GB RAM
Graphics: OpenGL 4.1 - ATI Radeon HD 5670, NVIDIA GeForce GT 640M
Network: Broadband Internet connection
Storage: 7 GB available space
So, no. Your processor and video card both have about half of the minimum speed