Roy Keane has stepped down as assistant manager with Aston Villa.
He wants to concentrate on his job as Republic of Ireland assistant boss.
In a statement, Keane said combining both roles had become too much for him and it wasn't fair to either Villa or Ireland.
He was only with Villa since July and he leaves them sitting just two points above the Premier League relegation zone, having won just three league games all season.
Keane’s statement said "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."
Villa manager Paul Lambert says he “respects” Keane’s decision.
"Roy came to me this morning and he informed me that, ultimately, the difficulty of combining both roles has prompted his decision, which I respect totally.
"In the brief period we have worked together he has been great in the role and I understand his reasons for leaving."
Meanwhile, the Midlands Club’s Chief executive Tom Fox said: "We thank Roy for his time at the club and we wish him the best with Ireland.
"Our focus now will be on working with Paul to identify the right person to work alongside him and to help us continue on our journey to return the club to its rightful place in the Premier League."
