How many times did they make this comparison? I think they are way off. Cardale doesn't have the bulk Leftwich had and can run the ball really well for his size.
I don't know who I would really compare Cardale too. But I would go closer to Cam Newton than Leftwich. Might as well compare him to JaMarcus Russell.
If I were to compare him, Maybe closer to Jason Campbell or Josh Freeman. but the sample size is seriously limited with passing stats. He runs nice though.