Today [if I can count right] would appear to be the final day under the FFA's National Grievance Resolution Regulations (7 business days from the initial decision) - that an appeal can be made, I would expect to see an announcement from the PFA and/or the Phoenix soon.
Should they appeal, a hearing would be set for within 21 days (i.e no later than the 21st) although given how close we are to the start of the season I would imagine it would be sooner than that.
It's worth noting that under the regulations any decision by the Appeal Committee would be final - there is no scope under the FFA Statutes for a matter of this type to be sent to the Court of Arbitration for Sport, and the regulations explicitly prevent any court appeal.