The Ashes 2010: Usman Khawaja called up as cover for Michael Clarke

The Australia vice-captain, Michael Clarke, insisted today that he will be fit for the first Ashes Test in Brisbane, but Cricket Australia is not so sure. The uncapped New South Wales batsman Usman Khawaja has been called up as stand-by in case Clarke fails to recover from the chronic back trouble that has plagued his career. "I understand better how to manage the injury these days – if I didn't I'd still be in Sydney having bed rest," Clarke said. But he was prevented from batting in the nets today as a precaution, so missing the chance to join his Australian team-mates in their first experience of ProBatter – the big screen that displays the run-up of a fast bowler and so takes practice against a bowling machine to a new level. England will feel they have stolen a march with ProBatter. They installed it at Loughborough this summer and have had footage available of most Australian bowlers. Australia's first glimpse of it, at the Allan Border Field in Brisbane, did not include any of the England attack. Clarke will bat at practice tomorrow as Australia nervously wait to see if he suffers any reaction to the injury that flared up again while playing for NSW last week. Khawaja would definitely replace him ahead of Steve Smith, the other reserve batsman in the party, even though Khawaja twice failed against England when playing for Australia A in Hobart last week. Khawaja would be a direct replacement at No4, so removing any need to move Marcus North or Mike Hussey up the order. Australia do not entirely share Clarke's confidence that he will be fit. Andrew Hilditch, the chairman of selectors, called Khawaja's call-up "prudent" but Clarke indicated that he will be given until "game day" if necessary to prove his fitness. "I am pretty confident, but obviously I am still a bit stiff and sore," Clarke said. "Our plan was for me to have a bat tomorrow and another on Wednesday and the goal is to get as close to 100% by Thursday. "I have this degeneration in my discs and sometimes it flares up. I have to do all the right things to get it as close to 100% as possible. I have had it so many times throughout my career that we know what treatment it needs and it doesn't feel too different to what it has in the past. Everyone has parts of their body that hurt more than others and with me it's my back." Clarke's back trouble questions whether Cricket Australia really can regard him as a long-term captaincy replacement to Ricky Ponting. Nobody can be entirely sure how much more resilient than Ponting, if at all, he will prove to be. He suffered badly during the 2005 Ashes Test at Old Trafford, damaging his back in the field on the first day, not fielding for the rest of the Test, but batting in both innings. He played down the suggestion that back-to-back Tests at the start of this series could ask too much of him. "I don't think so, I have played 64 Tests and never missed one, touch wood. This is a big series and I guess that's why we are taking it a little bit slower and why I didn't have a bat today. "If it was up to me I'd say let's risk it, get me out there. I want to play, but there are other things to think of, like it being a five-Test series. Then there is the rest of my career and other issues. We have to take the right decision for the team." Clarke questioned whether England really have it in them to retain the Ashes, laying particular emphasis on the quality of their pace attack. "I think they're high on confidence, but I'm not sure if they're better. I think 2005 was as good an attack as I faced in my career. I have always said that Harmison and Flintoff are the two hardest bowlers I've ever faced with Freddie being the No1 fast bowler I've faced in my career." Ponting, 7kg lighter for what might prove to be an Ashes farewell, admitted that he was concerned about the legacy he would leave for Australian cricket. If England win the series, it would represent Australia's third Ashes defeat under his captaincy. Only Billy Murdoch, in the late 19th century, has a worse record. "Of course I'm worried about a legacy," he said. "It's the reason I play the game and the reason why I cherish the captaincy so much. I want to make sure the team and the players are in a better position when I leave than when I started. I want to make sure I've got a really good, strong group of leaders under me when my time comes to move on. "That's why I spend so much time with the younger group. I'm generally the first on the training track and the last one to leave and most of that time is generally spent helping the younger guys out and understanding different things about the game."