WWE made a point of mentioning Sin Cara's charitable work when he returned to the company a few weeks back but proceeded to bury him on multiple occasions in matches against Andrade (going so far as to give him a female partner/manager only to then send her back to NXT a few short weeks later).
Now, he's taken to Twitter to confirm that he's asked for his release from WWE.
In the statement, he reveals that he came to the decision after a lot of prayers and consideration, consulting his kids and wife in the process. After noting that he's grateful to both WWE and the fans, Sin Cara added that he realises that he's stuck in a company where he is not valued and will never rise up the card.
He concluded by thanking everyone and it now remains to be seen whether WWE will actually release him from the company. They own the Sin Cara trademark and he's not the first Superstar to hold that title so perhaps he'll be replaced down the line in the role!