Lyon was the only spin bowler named in the 16-man squad for the five-Test Ashes series starting on July 10, but there is mounting speculation Pakistani-born leg-spinner Ahmed will be drafted into the side at his expense.
Former refugee Ahmed, 31, will be eligible if minor changes to Australia's citizenship legislation pass through parliament in the next few weeks.
Cricket Australia officials are privately confident there will be no complications, and if the amendment to the Citizenship Act passes he could apply for a passport and be in England by June 21, the Sydney Morning Herald said on Monday.
The squads for the Ashes lead-in events -- the ICC Champions Trophy and the Australia A tour -- left at the weekend, including Clarke, who played down the growing anticipation that Ahmed would join the team next month.
Chief selector John Inverarity has left open the possibility that Ahmed could be added to the initial 16-strong squad, announced in April.
