"It was a one-time exception created by the BBWAA and later ratified by the Veterans Committee."
I'm not sure that is correct.
Here on the Hall of Fame's website it says ...
Joss tragically died on April 14, 1911 – just two days after his 31st birthday – following a bout with tubercular meningitis. Though he only pitched nine big league seasons, the Hall of Fame Board of Directors passed a special resolution in 1977 allowing Joss to be considered despite the Hall of Fame rule that requires 10 seasons for election consideration.