A number of songs start out with a line such as 'last night I dreamed I saw...." or "I dreamed I saw...." etc etc.

Such as the song Joe Hill:
Full Lyric here:
Joe Hill
it begins like this:

I dreamed I saw Joe Hill last night
Alive as you or me
Says I, But Joe, you're ten years dead
I never died, says he
I never died, says he

So, you see, that type of opening line ins't all that unusual. Obvicously, you are referring to a baseball figure and not a Union Activist!

I think if you could provide us with where you heard the songs and metnion the name of the 'legend' who is the subject of the dream, we might be better able to help you. The more lyrics you can quite, the more we can help.