Ahhh, finally found it, blue post, edited yesterday
The practice phase of Arena Pass has come to a close, and the Rated Phase has now begun! This means that your matches will now count for your standing (and bragging rights!) when the Arena Pass comes to a close.
Rated Phase Begins – August 6
Rated Phase Closes – August 27
Rated Phase Begins – August 7
Rated Phase Closes – August 28