It's simple. It is an option when setting up the league. The league creator (in this case, me) can select fictional or real names. When everyone sees their AAA players for the first time, they have their real names. It won't specify which season, so a Steve Carlton could be the 82 23-game winner or the 5-9 87 Indians version. But with the names provided it's pretty easy to figure out which season it is.