|About the stats|
Over the course of his career, Roy Mahaffey pitched 1,056 innings and made 420 plate appearances. Mahaffey was worth 3.9 Wins Above Replacement (5.2 as a pitcher and -1.2 as a hitter) and -6.4 Wins Above Average (-5.2 as a pitcher and -1.2 as a hitter).
After adjusting for length of schedule, catchers, and relief pitchers, the 3.9 WAR becomes 4.2 adjWAR. Then, WAA is adjusted by ignoring negative seasons (thus, truly capturing a player’s peak seasons) and making similar adjustments for catchers and relief pitchers. After these adjustments, the -6.4 WAA becomes 1.7 adjWAA.
Then, the adjWAR and adjWAA are combined, but with extra weighting given to adjWAA. This gives Mahaffey 7.3 wWAR. wWAR is then converted to Hall Rating. A Hall Rating of 100 represents the Hall of Stats borderline (similar to OPS+ or wRC+, where 100 represents league average).
Roy Mahaffey has a Hall Rating of 7, leaving him nowhere close to induction to the Hall of Stats.
Want even more detail about the formula? See the About page.