Interesting the article stated Johnson batted .433 in the 1925 season, he had 97 at bats for the year. Must have really juiced the ball up that year.
It is interesting to note that Babe Ruth and Walter Johnson are 1-2 on the all-time wins-above-replacement list. Ruth had a career WAR of 182.6 and Johnson of 167.8. Cy Young and Barry Bonds are 3-4.
The first three accumulated those stats in 154-game seasons rather than the current 162-game season. Eight additional games over a 20+ year career is an additional season to accumulate stats with most of those additional games occurring during their prime.