Batsman Voges, 35, had been appointed Middlesex captain over the winter but, due to his first call-up to the Australia Test squad,??he will only be available for the??first four championship games.
A statement from Middlesex said: “All of us at Middlesex are naturally??delighted for Adam on his deserved inclusion in the squad, however this does??leave us with the difficult problem of needing to find a replacement overseas??player for the 2015 season with some immediacy.
“Given the record-breaking form that Adam has been in this winter in the??Sheffield Shield for Western Australia, his call up to the Australian squad??became increasingly likely with every run scored, and towards the end of the??Shield campaign became almost an inevitability, so we have for some time been??working on a contingency plan in the event that this became a reality.
“Conversations have been had, a shortlist of suitable players has been drawn??up, and in light of this morning’s announcement by Cricket Australia we can now??begin to formalise these plans to secure a replacement.”
Lancashire fast bowler Siddle has been a regular in the Australian Test set-up since his debut in 2008 and his inclusion was widely expected, but the county’s director??and head coach Ashley Giles said: “Although it’s pretty frustrating for us we are over the moon for Peter.
“When you sign an international bowler of his calibre there is always a??possibility that this will happen but we are still hopeful that Peter will be??available for the start of our LV= County Championship campaign.
“The hunt for a replacement begins now.”