One thing to consider is that minor leaguers will sometimes swing at, say, a fat changeup clearly below the zone. Every once in a while, they'll hit it. And when this happens, it's easy to think that they've been I submit that by "harder to pitch to," we mean "more difficult to plan for, because they will swing at pitches ordinary players wouldn't, and vice versa. Major league hitters have often noticed that certain pitches come on certain counts, or that a fastball normally follows a changeup, ect. Since they have expectations, they are more likely to sit on a particular pitch, and thus in a certain sense they can be more easily fooled. So, the "mind game" might genuinely be more difficult. For pitchers accustomed to using the hitter's expectations against him, it might genuinely be "more difficult" to generate a successful strategy, even though the hitters are less skilled and less likely to succeed. Also, I submit Prior So in Prior's opinion, it increases your reliance on others. And when a minor leaguer is playing in spring training or as a recent callup, often none of those other guys will know anything more than the pitcher. http://chicago.cubs.mlb.com/NASApp/mlb/news/article.jsp?ymd=20060604&content_id=1487788&vkey=news_chc&fext=.jsp&c_id=chc