diff --git a/R/get_df.R b/R/get_df.R
index 42eff9160..980e74e2b 100644
--- a/R/get_df.R
+++ b/R/get_df.R
@@ -341,7 +341,7 @@ get_df.serp <- function(x, type = "normal", ...) {
   if (identical(type, "residual")) {
     x$rdf
   } else {
-    get_df.default(x, type = type, ...)
+    Inf
   }
 }