Incorrect. There may be no clutch, but there is choke. I would argue that you can fall apart under stress of a certain level as a baseball player, but usually those guys don't make it to the majors, so there aren't many to tell you about. Bill James misses two pretty important things in his meandering non-argument. First, most players have similar statistics in clutch and non-clutch situations, given enough tries. There is a skill level that a player will eventually regress/progress to after a large enough sample size. The other one is even easier. David Ortiz, or any other hitter known as 'clutch' does not become stronger, quicker, or faster when it "really matters". His body is his body from any random at-bat to the next. He is biologically the same being in April (disregarding age) as he is October, or on Friday as he is on Thursday. To suggest otherwise is to suggest that he only gets 100% of his ability in certain situations, which signifies a lack of effort during non-clutch situations.