Perry reached out to McCaul and voiced his support around the time the House Homeland Security Committee chair's name surfaced as a potential primary challenger to Cruz, according to the Texas Tribune.
Questions about a potential primary challenge to Cruz began after the Texas senator declined to endorse Donald Trump at the Republican National Convention this summer.
Perry would not confirm to the Texas Tribune that he has encouraged McCaul to run, but a spokesman for the former governor did offer praise for the congressman.
"Rick Perry holds Michael McCaul in the highest esteem," Perry spokesman Stan Gerdes wrote in an email to the publication.
McCaul would not say whether he plans to challenge Cruz in an interview with the Texas Tribune last week, but he subtly jabbed the Texas senator for his focus on running for president.
"I think he's spent a lot of time since Day One running for president," McCaul said. "I think we deserve somebody in the Senate who is going to be representing the interests of the state of Texas."