A substitute is read as waiting on the bench for your chance, or replacing someone else. It reflects feeling secondary, or being ready to step in when needed.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.