[Leo_The_Lip]

Short answer: Yes.

The earliest date you can start is January 1, 1800. I've done that several times to test. As others pointed out, you'll have to pick a stats year. I've always used 1876, the earliest date. I've only used fictional players, but there is no reason you can't select an era of real players to use.

I'm reading a book about the true origins of baseball (NYC and Hoboken, not Cooperstown!) and the true pioneers--Candy Cummings did not invent the curve ball.

I have used mis-matched eras for stats and players several times with interesting results. You will enjoy this, so go ahead!