Sunderland manager Roy Keane has revealed that he transfer-listed Liam Miller because of the midfielder's persistent lateness.

The Irishman was told he could leave the club after failing on several occasions to turn up to training on time.

"The problem is Liam's time-keeping, it is a s simple as that. It is nothing to do with Liam as a player or as a lad," said Keane.

"I have got a lot of time for Liam, but we set a very high standard at the football club and, unfortunately, Liam has been unable to match that, so we have put him on the transfer list and we will see what happens.

"You have got to be on time for training. If a player is late once or twice, well and good; if he is late three or four times, maybe well and good.

"But when it goes beyond five, six, seven times then you have got to draw the line. In any walk of life, you have got to be on time."

It is not the first time Keane has taken a hard line over punctuality. Last season, Anthony Stokes, Marton Fulop and Tobias Hysen were left out of the squad to play at Barnsley because they missed the team bus bound for Yorkshire.

Miller was signed from Manchester United in 2006 following a season on loan at Leeds United. He has made 23 appearances for Sunderland this season.