A lo mejor

[cmon]

Estoy leyendo un libro de Angeles Mastretta (mexicana) y a lo mejor tu me puedes decir lo que significan "rengo" y "pirujerias."
:)Marsopa

Why is there an a in front of lo mejor?

[Rusty]

A lo mejor is an idiomatic expression meaning maybe/perhaps.

[cmon]

a lo mejor tu me puedes decir
:)Marsopa

Why is the subjunctive of poder not used with a lo mejor? I'm thinking it's because Marsopa has no doubt that you can actually can help her, but if she did have doubt, then she would have used the subjunctive.
Is that correct?

[poli]

I don't know if this answers your question about why it doesn't take the
subjunctive, but a lo mejor more often means probably which is close to perhaps but with a much more positive spin to it. Now that I think of it, perhaps (tal vez, quizás) doesn't take the subjuctive either.

[Rusty]

Why is the subjunctive of poder not used with a lo mejor? I'm thinking it's because Marsopa has no doubt that you can actually can help her, but if she did have doubt, then she would have used the subjunctive.
Is that correct?
Correct, if you believe what you're saying is true, the indicative tense follows a lo mejor/quizá(s)/tal vez. If, on the other hand, you aren't so sure, use the subjunctive.

[cmon]

Thanks , it feel good to be right sometimes, must be learning something.