Keane was appointed as Paul Lambert's assistant during the summer.
Keane only took the role up in the summer, alongside his duties as assistant to Martin O'Neill with the Republic of Ireland.
It is said that Keane made the decision to leave Villa Park as Paul Lambert's number two himself.
It isn't ideal preparation for the side, as Villa face a big game tomorrow against Burnley at Turf Moor where they go in search of their first league win in nine games.
When Keane initially took the post, he said: "I am relishing the prospect of linking up with Paul Lambert and combining both roles to the full advantage of both Villa and Ireland."
On his departure, Keane said in a statement: "Ultimately, my roles with Villa and Ireland and combining my commitment to these have become too much. It isn't fair to either Villa or Ireland, so I've made this decision.
"I'd like to thank Paul for giving me a great opportunity to come to a brilliant football club, I've really enjoyed my experiences at Villa and I wish the management team, the players, the supporters and the Club nothing but the best going forward."
Paul Lambert has confirmed he will begin his search for a new assistant 'as soon as is practically possible,' and said he respects the decision that Keane has come to.
He said: "In the brief period we have worked together he has been great in the role and I understand his reasons for leaving."