diff --git a/src/display/api.js b/src/display/api.js
index be607ac9f1f4d..3d16d97789a87 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -12,7 +12,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals requirejs, pdfjsLibs, __webpack_require__, __pdfjsdev_webpack__ */
+/* globals requirejs, __pdfjsdev_webpack__ */
 
 'use strict';
 
@@ -1121,7 +1121,9 @@ var PDFWorker = (function PDFWorkerClosure() {
         throw new Error('AMD or CommonJS must be used to load fake worker.');
       }
     } else if (PDFJSDev.test('SINGLE_FILE')) {
-      WorkerMessageHandler = pdfjsLibs.pdfjsCoreWorker.WorkerMessageHandler;
+      var pdfjsCoreWorker = require('../core/worker.js');
+      require('../core/network.js');
+      WorkerMessageHandler = pdfjsCoreWorker.WorkerMessageHandler;
       fakeWorkerFilesLoadedCapability.resolve(WorkerMessageHandler);
     } else {
       var loader = fakeWorkerFilesLoader || function (callback) {
diff --git a/src/pdf.js b/src/pdf.js
index 95ebb0f95ec87..1dc23daa0a9ff 100644
--- a/src/pdf.js
+++ b/src/pdf.js
@@ -28,11 +28,6 @@ var pdfjsDisplayAnnotationLayer = require('./display/annotation_layer.js');
 var pdfjsDisplayDOMUtils = require('./display/dom_utils.js');
 var pdfjsDisplaySVG = require('./display/svg.js');
 
-if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('SINGLE_FILE')) {
-  require('./core/worker.js');
-  require('./core/network.js');
-}
-
 exports.PDFJS = pdfjsDisplayGlobal.PDFJS;
 exports.build = pdfjsDisplayAPI.build;
 exports.version = pdfjsDisplayAPI.version;