I am befuddled by the amount of opinions depending on google search to figure out if the structure of a sentence is acceptable - believing if such a phrase is not found or rarely found in a google search, it must be "wrong".
For example, I cannot find a single instance of the following sentence in google. Does it mean its structure is "wrong"?
Multiply-adhered receptive media for transport of unencrypted machine control messages across the boundaries of highly mutated processes.
Anyway, you did not tell us what you meant by operation.
In the manufacturing industry there are processes. Within each process, there are individual operations. For example, the packaging operation, the cleaning operation, where an operation may be manned by an operator or technician.
Therefore, there is no disjoint in logic or grammar when
We assigned the new technician to an operation.
Let us say, it might be a military or police operation. There is nothing wrong in saying,
We had to assign experienced personnel to the operation. The operation is too critical.
However, if you had meant a mathematical or computational operation, we would have no idea what you would be trying to say,
He was assigned to the multiplication operation.
Perhaps, in a future new world order, where producing babies is part of a production line.
He was assigned to the reproduction operation.
Could you please explain what you meant by operation to avoid having us scratch our heads over this simple case?
Otherwise, there is nothing wrong in such a sentence.
Now that you have clarified it to be "hospital operation" ...
It is usual to say,
We assigned a doctor and a team of nurses to your surgical operation next week.
There are medical theses written on staff assignment to surgical procedures. Search/google for "assigning surgical operations".
It is probably presumed that we cannot logically assign a operation receiver to an operation, but than we can assign an operation or operation provider or performer to an operation.
- We have assigned the operation to the patient.
I wish to dispute that.
- We have assigned the new product to an existing operation.
- We are assigning the patient to Dr Rachmat.
- The patient has not been assigned an operation yet. We are still investigating which procedure would suit her condition best. When we have the sufficient information, we will be able to assign the patient to the appropriate surgical operation.
- Have you figured out what is appropriate for the patient? Have you assigned the patient to an operation yet?