He made this announcement on his Twitter account:
You can view the tweet itself here: https://twitter.com/RichardsWesley/s...73195212349441
Richards, if I recall correctly, had said that 2017 would be his final year for in-ring competition, citing the same medical school conflict that has apparently reached an impasse.
While I'll miss him personally, it does feel like he and Eddie Edwards have reached critical mass through their run with the company, or at least Richards certainly has.
Best of luck in the future and thanks for the memories!