The current shape that they're in, not if they trained specifically. A friend and I were debating.
You figure the only ones who would have a chance are cornerbacks, safetys, wide receivers, running backs, and a select few quarter backs. Linebackers, lineman, tight ends, etc. are way too big.
My initial thought was no. But after thinking, and given the huge number of athletes in the NFL, I could see it being possible.