"This is another strong group and we go into this series having answered a few questions of ourselves against Malaysia," Batch said.
"The addition of Bradley and Stephen will add another dynamic within the group while we are really excited about seeing a fantastic young talent in Hayden test himself at senior international level.
"We have an open selection policy and aren't afraid to look at our options even at this stage of our campaign. The most important thing for us is that we are able to assess our players and find the best group to send to the Rio Olympics."
Marcus Child, Jacob Smith and Jared Panchia come out of the extended team of 21 which played against Malaysia, along with defender Alex Shaw who had successful surgery on Thursday to repair a fractured cheek and eye socket he suffered in the third test.
The Black Sticks play Korea this Wednesday and Thursday at 7pm with a further two games on Saturday and Sunday at 3pm.