Matt Prior must shake himself out of his miserable run of form before the Ashes are gone, says Mike Atherton.
Wicketkeeper-batsman Prior has faced just 10 deliveries in the series so far, making two ducks and scoring just four runs - his latest failure coming when he was caught behind off Mitchell Johnson on day three of the second Test for nought as England were bowled out for 172.
Prior became the first wicketkeeper to be named England cricketer of the Year in May but has struggled this year, averaging just 19 in the summer's 3-0 Ashes success since when his form has dipped still further.
Jonny Bairstow was placed on stand-by with the gloves before the first Test of this series as Prior struggled with injury but wasn't required as the Sussex player proved his fitness.
Now Prior - who nicked Johnson behind after avoiding two bouncers - has to prove he has what it takes to score runs at number seven, says Atherton.
"Matt Prior was softened up," Atherton told the Sky Sports Ashes Podcast. "He's horribly out of nick - he hasn't got runs for a year now, or thereabouts, but it was a good bit of bowling.
"Prior's form - with the bat, that is - is very concerning. His wicket-keeping is excellent, as it always is but he has been in a batting slump for some time now - ever since the start of the New Zealand series.
"He was feted after the year he'd had - he was named England's player of the year - and it's amazing how quickly things can turn in the game and how you can't stop it if you get on a bit of a slide and a slump.
"Prior is in that spiral now. He's a very experienced, tough cricketer but he's got to get it out of that slump very quickly."
Only three England batsmen have scored fifties in the series so far - Alastair Cook, Michael Carberry and Ian Bell - as the tourists have mustered totals of 136 and 179 in Brisbane and 172 in Adelaide.
Atherton says that the manner of England's dismissals is as concerning as the frequency of them, and highlighted Pietersen's downfall - caught by George Bailey at midwicket off Peter Siddle - as a prime example.
"Kevin Pietersen's was a poor dismissal - there were two short mid-wickets in place," he said. "The fielders are not there for decoration, they are there for a reason.
"The worrying thing for England is this kind of recurring theme of batsmen getting out in similar ways. Pietersen was caught at midwicket at the Gabba and again today, Swann went the same way [driving] and Broad was bowled behind his legs.
"England are definitely being worked over by some good Australian strategy and some high-class fast bowling.
Already 1-0 down in the series, England's chances of escaping defeat in Adelaide appear slight after closing day three some 530 runs behind Australia, who reached 132-3 in their second innings after opting not to enforce the follow-on.
"England have a very slim chance of saving the game," said Atherton. "Nothing is inevitable in the sense that it's still a decent enough surface and England have good players who can play match-changing innings.
"But you are talking about a one per cent chance. Australia have virtually got this game nailed down and if there's no rain you'd expect England to go to Perth 2-0 down - and no England team has ever come back from 2-0 down."
He added: "It's hard to see them doing that because Australia look a much superior side. All of us were expecting a close series at the start, with many of us expecting England to just prevail, but at the moment there is clear-blue water between England and Australia.
"Australia are getting bags of runs while England can't pass 200. Australia have got quicker bowlers at the moment and bowlers who are creating more energy at the moment."
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See if England can save the second Test - our live coverage of day four begins at 11.30pm on Sky Sports 2. Before that, catch up with The Ashes Verdict from 9pm and The Ashes Extra from 11pm on the same channel.