For the same reason I never use sp_rename to rename object in sql server.

Always prefer if exist method.

if exists (select * from sys.objects where object_id = object_id(N'[dbo].[Object_name]') and OBJECTPROPERTY(object_id, N'IsProcedure') = 1)

drop procedure [dbo].[object_name]

GO

Create procedure dbo.object_name

as