It may very well be an indicator of future success or lack there of, but the games have already been played and someone is trying to make a statement about that finite set of games. In some discussions sample size is irrelevant, because the size of the sample is the point of the discussion. I doesn't take a rocket scientist to understand that there are going to be peaks and valleys in performance over 162 games. This is the disconnect. People normally don't talk about past performance as just that, past performance. It's usually "player A has been terrible, so how could you think they will ever be any good, bench/DFA him!" There are years and years of statistics that show the wild fluctuation in player production from year to year, due to simple statistical selection, the luck inherent in where a baseball goes when it's hit and player improvement/regression. Sometimes projections don't mirror what actually happens, but of course there's no way it's possible to be exactly right. Sometimes a player finally "gets it" and improves, sometimes they produce less due to injury or other factors. Of course sometimes, projections nail reality, such as the White Sox in 2007 and the Tampa Bay Rays of 2008.