Nuwan Pradeep ruled out of CWC19 through illness
The 32-year old has taken five wickets thus far in the tournament at an economy rate of 5.41, helping Sri Lanka to wins over England and Afghanistan.
He missed the last game, as his side succumbed to a heavy defeat at the hands of South Africa, and he has departed from the squad with Rajitha immediately taking his position.
26-year old Rajitha last appeared for his country on 13 March in an ODI against South Africa, and he has five wickets from his six matches to date in the format.
Sri Lanka have two matches remaining, against West Indies and India, and require results to go their way if they are to achieve semi-final qualification.