diff --git a/src/csharp/Grpc.Core/Internal/DefaultDeserializationContext.cs b/src/csharp/Grpc.Core/Internal/DefaultDeserializationContext.cs
index bac7bbe4c59..946c37de190 100644
--- a/src/csharp/Grpc.Core/Internal/DefaultDeserializationContext.cs
+++ b/src/csharp/Grpc.Core/Internal/DefaultDeserializationContext.cs
@@ -82,14 +82,11 @@ namespace Grpc.Core.Internal
             return instance;
         }
 
-#if GRPC_CSHARP_SUPPORT_SYSTEM_MEMORY
         private void FillContinguousBuffer(IBufferReader reader, byte[] destination)
         {
+#if GRPC_CSHARP_SUPPORT_SYSTEM_MEMORY
             PayloadAsReadOnlySequence().CopyTo(new Span<byte>(destination));
-        }
 #else
-        private void FillContinguousBuffer(IBufferReader reader, byte[] destination)
-        {
             int offset = 0;
             while (reader.TryGetNextSlice(out Slice slice))
             {
@@ -98,7 +95,7 @@ namespace Grpc.Core.Internal
             }
             // check that we filled the entire destination
             GrpcPreconditions.CheckState(offset == payloadLength);
-        }
 #endif
+        }
     }
 }