Pakistan will not only have to win the remaining three matches, starting with New Zealand, but also hope that the results in other matches favour them to salvage any hopes of a semi-final berth.
England go into the 10-team tournament as the top side in the team rankings with 125 points and India in second position four points behind.
The PCB banned Shehzad for violating anti-doping regulations after he tested positive for a prohibited substance in May and his suspension was scheduled to end on November 10.
From Brian Lara to Virat Kohli, Ben Stokes to Steve Smith, the ICC Under-19 Cricket World Cup has never fallen short of showcasing cricket's brightest young stars. More than 30 years have passed since the world's top talents first announced themselves on the big stage, with the 1988 Youth Cricket World Cup a ground-breaking step in bringing ability to the fore.
England, who have won both the one-day and Twenty20 series against Sri Lanka, play a two-day practice match in Colombo before heading to Galle which hosts the first of the three Test matches from November 6.
Rajneesh Gupta presents all the fascinating career numbers of players in the World Cup.