Rizwan and Irfan both suffered hamstring injuries in the third match in Rawalpindi, where a second-string New Zealand side won by seven wickets to level the five-match series 1-1
West Indies toured England for a test series in July and are currently in New Zealand to play three Twenty20 Internationals and two Test matches.
CWI Chief Executive Johnny Grave said in a statement that "... with the health and safety of our touring party at the forefront of our minds, we have decided to conduct a pre-tour recce by sending two highly experienced professionals to assess the BCB's bio-secure plans and protocols."
However, Bangladesh board chief executive Nizamuddin Chowdhury said last week the CWI had requested one fewer Test to reduce the amount of time their players would have to spend in the biosecure bubble.