Want to talk impact.... Gibson's '68 season and his 1.12 era that year was the reason MLB lowered the mound the following season.
It was Gibson,
plus * Don Drysdale breaking Walter Johnson's shutout inning streak over six consecutive shutouts in May and June.
* Denny McLain earning 31 wins. (Codicil: When you're getting 4.7 runs of support per 27 outs, which is what McLain got in 1968, you'd damn well
better win 31 games.)
* Carl Yastrzemski winning the American League batting title at .301.
* The American League slugging a mere .339. (It's still the lowest league percentage since 1915.)
* 339 shutouts across MLB.
* Five teams pitching 20 or more shutouts. (In descending order: the Cardinals [30], the Mets [25], the Indians [23], the Dodgers [23], and the Giants [20].)
* A collective MLB 2.98 ERA
and fielding-independent pitching rate.
* Luis Tiant of the Indians winning the American League ERA title with 1.60.
*
Far more night than day baseball---578 more night than day games in 1968, and 472 more night games in 1968 than in 1963, the year the Baseball Rules Committee expanded the strike zone to points from the batter's shoulders to below his knees.
Gibson's 1968 ERA was only the most obvious reason MLB re-instituted the pre-1962 strike zone and lowered the mound to ten inches. But it wasn't the
only reason. If Gibson had rolled that ERA but everything else in MLB remained at its previous or future averages, by itself it wouldn't have been enough to compel those rule changes. Bob Gibson was a great pitcher, but his impact on the post-1968 rule changes is as exaggerated as his image for headhunting.
