|About the stats|
Over the course of his career, Al Mattern pitched 844 innings and made 306 plate appearances. Mattern was worth 4.8 Wins Above Replacement (5.8 as a pitcher and -1.0 as a hitter) and -1.7 Wins Above Average (-0.6 as a pitcher and -1.0 as a hitter).
After adjusting for length of schedule, catchers, and relief pitchers, the 4.8 WAR becomes 5.1 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 -1.7 WAA becomes 0.9 adjWAA.
Then, the adjWAR and adjWAA are combined, but with extra weighting given to adjWAA. This gives Mattern 6.7 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).
Al Mattern has a Hall Rating of 6, leaving him nowhere close to induction to the Hall of Stats.
Want even more detail about the formula? See the About page.