i lost what i was writing, stupid back button. do 162x16x9 to get the number of innings in a year (approximate since it wont take into account bottom of the 9ths not played and extra innings), then figure out what the frequency of batting around should be (last year's NL OBP was .343) then multiply by the number of innings in a year. from there we'd have to figure out the frequency of pinch-hitter use and assume that a pinch-hitter bats twice in 1/9th of all innings in which the team bats around, 1/4.5 of all innings where 10 hitters come to the plate, etc. too much work for me, but that would be the framework to figure out the likelihood of it happening. quick googling shows me that this year on april 13th chad moeller pinch hit for aaron harang in the top of the 5th and then batted again later that inning.