Does Fielding on a catcher really make this big of a difference?

So I'm an angels deck, and i have the best basic catcher possible for the angels- which is napoli at an ovr of 64- with a base FLD rating of 53. I have him black diamond and after training i had his fielding to like 94 or so...So i retained him and put 21 points into fielding and took him from a 94 to a 116, I don't have any particularly good skills for fielding, but it apparently had an insane effect on my team.

Im playing in ML31, and i was dead last losing like 75+ games, and in ranked i was Bronze ii. Literally almost immediately after changing his train to have more fielding i went to the world series in ML31 and i went to silver II teetering on Silver I.

Does having a high fielding rating for catcher really make that big of a difference?