The left-arm pacer felt discomfort in his left shoulder before he was to bowl the last ball of the innings against Zimbabwe in the second Twenty20 International in Mirpur on Sunday
Having watched Mustafizur clutching on to the shoulder with his other hand, Tamim Iqbal ran up to the 20-year-old and advised him to leave the field immediately.
"The injuries are old for him -- both the shoulder strain and the elbow injury. So we didn't take any chances though he had just a ball remaining. We wanted to get him treated as soon as possible," Mashrafe said.
"Although the matter is of concern at the moment, usually nothing serious happens from these injuries. I hope it really isn't and that he recovers."
Bangladesh lead the four match Twenty20 International series 2-0 with the third match to be played here on Wednesday.