Ajmal Shahzad was ruled out Wednesday of the England squad for the first Test against Pakistan, starting at Trent Bridge here Thursday, with an ankle injury. Shahzad's place in a 12-man squad has been taken by fellow Yorkshire seam bowler Tim Bresnan. England and Wales Cricket Board (ECB) chief medical officer Nick Peirce said in a statement: “After twisting his left ankle with Yorkshire over a week ago Ajmal went on to successfully play in a 40-over match for his county last Monday. “Unfortunately Ajmal felt some discomfort following England practice at the NCPC (National Cricket Performance Center) Tuesday and as a precautionary measure it is felt he is best to undergo rehabilitation on the ankle for the remainder of this week.” Shahzad, 25, has so far played just one Test, against Bangladesh in Manchester last month, where he took 4-63. Paul Collingwood is adamant there is no reason why he or his fellow England batsmen should feel daunted by the challenge of facing Pakistan's bowlers here. Pakistan's teenage left-arm quick Mohammad Aamer has been compared to Pakistan hero Wasim Akram while Mohammad Asif was likened to Australia great Glenn McGrath by Pakistan captain Salman Butt. Umar Gul is a fine third seamer while leg-spinner Danish Kaneria completes an admirably balanced attack. However, Collingwood – returning to Tests after missing England's early season 2-0 home series win over Bangladesh with a shoulder injury – suggested Pakistan was flattered by overcast conditions at Headingley. “I don't want to go overboard on ‘these guys are the best thing since sliced bread' – or Wasim Akram, or this, that and the other,” Collingwood told reporters Tuesday. Nevertheless he praised the 18-year-old Aamer, saying: “When I was 18 I was just getting a contract for Durham and playing club cricket out in Australia – so it was bare bones at the time. Seeing a youngster like that (Aamer) is excellent for the game. “To say they're the No. 1 bowling attack in the world I would say was over the mark. Their confidence is going to be sky-high. But we're a confident team ourselves.” England will take heart from the way an inexperienced Pakistan batting line-up lost seven wickets in pursuit of a relatively modest victory target of 180 at Headingley. Pakistan, in what will be only opening batsman Butt's second match as captain, are likely to go in with the same side as played at Headingley. Meanwhile England, which has a 12-man squad, is set to stick with a policy of six specialist batsmen and four bowlers that has become standard under the regime of coach Andy Flower and captain Andrew Strauss.