Why was spitball allowed to some players?

Question

Wikipedia has this to say on the history of banning spitball:

The spitball was banned in two stages. In the winter of 1919–1920, managers voted to partially ban the spitball, allowing each team to designate at most two pitchers who would be permitted to legally throw spitballs. Then, following the 1920 season, the spitball was banned leaguewide, except for existing spitballers who were grandfathered in and allowed to keep throwing the pitch legally until they retired.

The first stage looks highly surprising, but somewhat fair. It's a way to allow some spitballs in the game but not all spitballs.

The second stage puzzles me. Did this decision lead to inequality of rules between players and teams? Was such inequality real, and seen as a problem? Were there any considerations that made banning spitball for everybody impractical?

Answer 1

It wasn't allowed for some players. It was a rule that used a cut off date. If you were pre-1920 and threw spitballs before, you can throw them after.

If not, no more spitballs. Meaning the last time a spitball was legally thrown was probably around 1935 given there was a younger spitballer in 1919. Since then it has been banned.

That doesn't mean it wasn't thrown, it just means it wasn't thrown legally. There have been a number of players that have made their careers on spitballs. One of their key traits was the ability to throw it and not get caught.

There are rules all over sports exactly like this. For instance in baseball and hockey the playing with a helmet was not forced outright to vets who had played without.

As far as the spitball usefulness this is directly related to the spin rate of the ball. With a substance that makes a ball slippery a player can achieve a much better spin rate. This will account for any type of curve/breaking ball having a more drastic turn (whatever way it will turn).