A polymerization process is provided. For example, a polymerization process is described, including providing a catalyst slurry having a metallocene catalyst and a first oil, providing a transport medium including a second oil and combining the transport medium and the catalyst slurry to form a catalyst mixture. The process may further include introducing the catalyst mixture to a polymerization reactor and contacting olefin monomers with the catalyst mixture to polymerize the olefin monomers and form polyolefins.