What people often forget about Ruth is that he was one of the best pitchers in the American League for about five years with the Red Sox.
But even if he had started out as an outfielder with the Red Sox, chances are he wouldn't have been clouting the amount of home runs he hit with the Yankees.
At the time he came into the league, 1914, it was still the dead ball era. Although baseball had introduced the cork-centered ball in 1911, they still used beat up/nicked/altered balls throughout the game.
It wasn't until 1920 after one baseball player was hit and killed by a pitched ball, Ray Chapman, that the league started the habit of throwing out beat up/altered balls and using new baseballs. They also outlawed foreign substances like saliva and other things to be applied. They did grandfather in pitchers currently in the league who used now-illegal substances. Burleigh Grimes for example.
But Ruth still hit 29 home runs with Boston in 1919 before the changes went into effect. That means if he had played regularly as an outfielder when he entered the league, he might have hit an extra 100 homers or so to add to his total of 714. His total homer output would probably have been around 800 or more.
That means to match that total, a player would have to average 40 homers for twenty years.
