Originally Posted by MrCinatit
The only reason Koufax's run did not extend further is that he retired young (30) due to injury. Basically, he was also voted in because of what could have happened, such as Addie Joss (imagine the number he could have put up...).
Foster, on the other hand, continued his career for quite a while after his monster run - much of it being injury free, I believe, though the '81 strike did rob him of potentially another large year.
Foster's number decline came mostly due to age (his numbers drop off significantly after 33), and arguably a departure from Cincinnati and appearance with the Mets.
Baseball reference compares his stats to Gil Hodges, Willy Horton, Tino Martinez, Jack Clark and Del Ennis. Five very good players, but none are quite HOF caliber.
I was just pointing out that on a rare occasion, 4 great years in a row can lead one to a HoF.
I was never intending to compare Foster and Koufax's careers; obviously George had a lot more time (ultimately, to cool off) than Sandy K did.