Hiding Case Owners Dynamics CRM 2011

Good day guys,

We are trying to hide Case Owners in DCRM 2011 without loosing historic case data, I have added an if statement in the form field for owner that should set the visibility to false. 

The script looks as follows:

if (oOwner.getValue() != null) {
switch (oOwner.getSelectedOption().text) {

case 'Owner Name':
oOwnerEmail.setValue("Owner Mail");
oOwnerDirectPhone.setValue("Contact Numer");
break;

}

Xrm.page.ui.controls.get(oOwner).setVisible(false);

}

Any suggestions?

Thanks!