All-rounder Saifuddin has been replaced by Taskin Ahmed midway in the match as he showed signs of concussions.
A nasty short ball from Chameera pinged Saifuddin on the helmet as he missed the hook during the 47th over.
Saifuddin took his helmet off and got medical attention in the dressing room.
The Bangladesh Cricket Board (BCB) confirmed the news through a press release.
"Bangladesh allrounder Mohammad Saif Uddin was hit on his helmet while batting in the second ODI. He has shown signs of concussion and for his safety, Saif Uddin is being substituted on the match by a like for like player Taskin Ahmed," the BCB press release read.
Taskin is Bangladesh's first-ever concussion sub in ODI.
Saifuddin scored 11 off 30 balls before getting dismissed.