Pakistan opener Fakhar Zaman (34) was ruled out of the Champions Trophy on Thursday with an abdominal muscle injury and Imam ul-Haq (29) has been called up as his replacement.
Fakhar hurt himself while chasing a ball during Wednesday's defeat by New Zealand and spent significant time off the field, which meant he could not open the innings.
Batting at number four instead, Fakhar looked in discomfort and made 24 as Pakistan folded for 260 in reply to New Zealand's 320-5.
The tournament's event organising committee has approved left-handed opener Imam ul-Haq as the replacement, the International Cricket Council said in a statement.
Pakistan must beat arch-rivals India in Sunday's blockbuster in Dubai to keep their title defence alive in the eight-team tournament.