diff --git a/src/Microsoft.AspNetCore.Authorization/project.json b/src/Microsoft.AspNetCore.Authorization/project.json
index f07e8d2d5d..511a05d56c 100644
--- a/src/Microsoft.AspNetCore.Authorization/project.json
+++ b/src/Microsoft.AspNetCore.Authorization/project.json
@@ -14,7 +14,11 @@
     "Microsoft.Extensions.Options": "1.0.0-*"
   },
   "frameworks": {
-    "net451": {},
+    "net451": {
+      "frameworkAssemblies": {
+        "System.Runtime": { "type": "build" }
+      }
+    },
     "netstandard1.3": {
       "dependencies": {
         "System.Security.Claims": "4.0.1-*"