Mohammad Hafeez has failed to make the cut for Pakistan's World Cup squad due to an ankle injury sustained during the second one-day international against New Zealand.
The opening batsman has been advised to rest for at least three weeks, paving the way for Saeed Ajmal's possible inclusion.
Pakistan have already suffered three major blows ahead of the showpiece tournament, with paceman Umar Gul and fast bowler Junaid Khan both having been omitted because of injury problems of their own.
"Hafeez has been ruled out of the World Cup and will return home with the first available flight and in his place Nasir Jamshed has been summoned," a Pakistan Cricket Board spokesman said.
Ajmal was due to miss the World Cup while his controversial bowling action was being cleared, but after being given the green light by the International Cricket Board, he is now in contention to play.
