Baseball is all about individual matchups so I think that lends to more mental mistakes and advantages. why would you think that) Eh, a good hitter could go up against a great pitcher and lose confidence. Also, baseball is the only sport where they're basically playing ever day. There are all sorts of mental things that can go on over the course of 6 months that aren't quantifiable And if that lack of confidence manifested itself then it would result in a quantifiable decline in production. If you were a talented hitter that regularly lost confidence against good pitchers you would probably wash out of the league, if not the minors. Fair point. But there are other external factors that could affect a player: sick child, marital problems, depression, etc.