Basically, you're more than 100 "points" below what the average player is producing. So like Wolf said... you can go over 200, so you can go below 0. yeah, it means you're pretty awful That doesn't make sense, because OPS+ is a normalization, right? It's OPS/LeagueAverageOPS*100*park factor, right? None of those numbers should be negative, so how is the result negative? perhaps the park factor makes it negative, meaning Murton's 3 for 30 line might be an OPS+ of 0 in certain parks, but in the parks he played in, those numbers end up being even worse than "0" Park factor is scaled from 0-infinity, too, so it can't be negative, either. Someone (baseball-reference?) must be using a definition of OPS+ that is different from the one I'm used to, there is no other way to get negatives into the equation.