How do Major Leaguers perform after cutting their hair?

In a biblical version of Like Mike, Samson's strength was dependent on the length of his hair. If someone were to snip his beloved locks, he'd lose the outrageous strength that made him basically undefeatable in battle. 
But is it also the case that when long-haired baseballers trim their dos, they also cede their powers and revert into mere mortals?