Top-order batsman Najmul Hossain Shanto was ruled out of the remainder of the Asia Cup on Tuesday with a hamstring injury and faces a race to be fit for the World Cup.
Najmul is the leading scorer at the Asia Cup with 89 and 104 against Sri Lanka and Afghanistan respectively to help Bangladesh into the last four.
Najmul felt some discomfort in his left hamstring during his innings against Afghanistan in Lahore on Sunday, Bangladesh Cricket Board (BCB) said.
"The player had complained of hamstring pain during batting and could not field. We had an MRI scan done confirming a muscle tear," team physio Bayjedul Islam Khan said.
"As a precaution, Shanto will not take any further part in the tournament and will be returning home to start rehab and prepare for the World Cup."
The one-day World Cup in India starts on October 5.
Najmul is Bangladesh's top run-scorer in 2023 across all formats with 1,078 runs, including four hundreds and five fifties.
News of his injury came a day after batsman Liton Das was declared fit to join the squad having recovered from a fever that forced him to miss the Asia Cup group-stage matches.
Bangladesh have also lost frontline seamer Ebadot Hossain while all-rounder Mehidy Hasan Miraz retired hurt against Afghanistan after making a career-best 112.
Bangladesh face Pakistan in Lahore on Wednesday in the Super Four.