Hard to be in second place when you're not officially running. Where he'd pop in if he does I have not seen polls on (not saying they don't exist, just that I haven't seen them), and I also wouldn't trust such polls anyhow. I'd want to see at least a month to settle in, the very first such poll results tend to be more "Do you recognize the name X?" rather than "Do you want X to be President?" Same is true of the very first primary polling for any run. (We're only mostly past that right now.)