I believe the only slider that affects franchise simulations is the Injury slider. Something to keep in mind with all these simmed stats, while they look really good they would probably look even better if the injury slider was moved up before simming. I did some research last year and found simming with injury slider on 10 gave the most accurate amount of injuries per month/season. We assume that many injuries is unrealistic but as in many cases the statistics say otherwise. I found out how many players go on the DL every year per team and felt pretty confident injury slider 10 was most realistic for simming. In-game is a different story. I believe 1.5 injuries per week was the number I found of injuries per MLB team. I'll be testing that again this year but I am sure i'll find raising injuries will be the way to go for accuracy's sake.
It would be pretty easy to just adjust a handful of player ratings of some pitchers if you really wanted to see lower ERAs. I prefer playing with Willard's Hybrid roster that rerates every player (MLB + minor leaguer) according to ZiPs projections for 2014 which uses OSFM as a base but that won't be out for a few months. You can find that in the Roster forum!
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