Mashrafe, who took 12 wickets in three games in Kenya last month including a Bangladesh record six for 26, sprained his right ankle on Friday when he slipped down the stairs at his home and will miss training for up to 10 days.
''We are monitoring his condition closely. At this moment it looks he will be okay within the time, but to become sure we have to wait a few more days,'' chief selector Faruk Ahmed told Reuters today.
Faruk was more worried about the condition of Mashrafe's bowling partner Rasel, who damaged his foot in a motorbike accident last week.
''Rasel did not improve on the scale we expected of him,'' Faruk said.
Shahadat Hossain is now the only fit pace bowler in Bangladesh's 14-man Champions Trophy squad.
Bangladesh will play in the qualifying phase against Sri Lanka, West Indies and Zimbabwe from October.7-14. The main tournament starts on October.15.