diff --git a/src/display/api.js b/src/display/api.js
index c6e7befb8..6cc2daa5f 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1746,12 +1746,7 @@ const PDFWorker = (function PDFWorkerClosure() {
         return mainWorkerMessageHandler;
       }
       if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
-        if (typeof SystemJS !== "object") {
-          // Manually load SystemJS, since it's only necessary for fake workers.
-          await loadScript("../node_modules/systemjs/dist/system.js");
-          await loadScript("../systemjs.config.js");
-        }
-        const worker = await SystemJS.import("pdfjs/core/worker.js");
+        const worker = await import("pdfjs/core/worker.js");
         return worker.WorkerMessageHandler;
       }
       if (
diff --git a/web/app.js b/web/app.js
index fafb1d368..53a1bff38 100644
--- a/web/app.js
+++ b/web/app.js
@@ -2026,12 +2026,7 @@ async function loadFakeWorker() {
     GlobalWorkerOptions.workerSrc = AppOptions.get("workerSrc");
   }
   if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
-    if (typeof SystemJS !== "object") {
-      // Manually load SystemJS, since it's only necessary for fake workers.
-      await loadScript("../node_modules/systemjs/dist/system.js");
-      await loadScript("../systemjs.config.js");
-    }
-    window.pdfjsWorker = await SystemJS.import("pdfjs/core/worker.js");
+    window.pdfjsWorker = await import("pdfjs/core/worker.js");
     return undefined;
   }
   return loadScript(PDFWorker.getWorkerSrc());