diff --git a/source/includes/options-mongorestore.yaml b/source/includes/options-mongorestore.yaml
index d3d5f33e100..94df09f42a8 100644
--- a/source/includes/options-mongorestore.yaml
+++ b/source/includes/options-mongorestore.yaml
@@ -257,6 +257,15 @@ description: |
   current state of the database reflects the point-in-time backup captured
   with the ":option:`mongodump --oplog`" command. For an example of
   {{role}}, see :ref:`backup-restore-oplogreplay`.
+  
+  To find the oplog entries it should replay, mongorestore looks for a
+  file named oplog.bson immediately below the dump directory.  This is
+  where ":option:`mongodump --oplog`" places the oplog that it generates,
+  but you can place any oplog there, for example a dump of an existing
+  oplog that you created with mongodump (in this case, the oplog will likely
+  be dumped under the name oplog.rs.bson, and you will have to rename it to
+  oplog.bson and place it into the top-level directory of the dump in
+  order for mongorestore to replay it).
 optional: true
 ---
 program: mongorestore