i believe it's actually the 30th. At least that's what i have read as far as Rudy Gay's opt out situation with the Kings is concerned
Is there a deadline for players to exercise their ETOs?
Next Monday, the 23rd, when the players have to inform their teams of their opt-in/opt-out, so we'll get the ball rolling in a week's time.
In that case, I think it's different days for each contract. I swear I read someone's was the day before, or after the draft.
So it may not be a league wide date, but contract by contract.