Diffrent rules apply to diffrent leagues but I can give you the rules of the league I play in. We have a 28 man roster with daily roster changes. We start 1 each at c, 1b, 2b, 3b, ss, 3 of, 2 utility. 3 Sp, 2 rp, 2 any pitchers. Now with the daily changes you can switch your starters in and out as they pitch. The rest of the roster posistions are used for bench spots.
There will come a day when Barry Bonds leaves baseball, and everything about the game will be the better for it.