|About the stats|
Over the course of his career, John Mullen made 3 plate appearances. Mullen was worth -0.1 Wins Above Replacement and -0.1 Wins Above Average.
After adjusting for length of schedule, catchers, and relief pitchers, the -0.1 WAR becomes -0.3 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 -0.1 WAA becomes 0.0 adjWAA.
Then, the adjWAR and adjWAA are combined, but with extra weighting given to adjWAA. This gives Mullen -0.3 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).
John Mullen has a Hall Rating of 0, leaving him nowhere close to induction to the Hall of Stats.
Want even more detail about the formula? See the About page.