Jim MaxwellAustralian Broadcasting Corporation & BBC Test Match Special
"David Warner has history. He is a kid from the back blocks, who has a lot of talent.
"He is vital to the team, although he has no form at all in his last 10 innings and it is a while since he last made some runs.
"He is the one player alongside Shane Watson who can give some momentum to an innings. So, without Michael Clarke, it will be a big loss."
BBC Radio 5 live's Pat Murphy said: "I believe it happened around 02:00 (BST) at the Walkabout bar in the centre of Birmingham.
"There was a private VIP area and some of the Australia players were in there. The three England players, Joe Root, Stuart Broad and Chris Woakes, were some way away and were larking around - wearing silly wigs and that.
"I understand Warner took umbrage and went over to Root and glanced him on the chin.
"I am hearing that Broad put his arm around Root as soon as it happened and said 'time to go back to the hotel' and I am also told that they were not worse for wear.
"One thing that is important to say is that since 13 May the England players, particularly Root and Broad, have not had a day off.
"The evening of the eighth of June was identified as down time. The matter is closed as far as the ECB is concerned."
In one-day internationals, Warner averages 29.81 from 38 innings, with a strike-rate of 80.58, while in Tests, he has made three centuries and seven fifties in 19 appearances, averaging 39.46.
Yorkshireman Root has excelled since making his debut for England with a patient first-innings 73 in the
drawn fourth Test
against India last December.
The 22-year-old has since gone on to average 42.40 with the bat in the Test arena, while he has scored 429 in 11 one-day international innings at a strike-rate of 83.95.
This is the second time in three weeks Warner has been in trouble with authorities.
Last month, he was
for comments to journalists on his Twitter account.
The tweets, some containing obscene language and which Warner later apologised for, appeared after a journalist criticised the Indian Premier League (IPL) in an article which used a picture of him.
The game in Birmingham between England and Australia was the start of a hectic schedule in which they will meet in
home and away Ashes Test series,
as well as Twenty20 and one-day international fixtures.
England will begin the defence of the Ashes at Trent Bridge on 10 July.
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