So, yes, no, you have to, and what sorcerer do you mean?
This has been done before, and, in general, it's a better use of your time to look for rules that support what you want to do. You CAN write them yourself, but why? A more experienced game designer has already done this...
You might want to look at the Dragon Lords of Melnibone, or Iron Heroes, or the Conan RPG, or the Living Death 3.5 sourcebook, or the Black Company sourcebook. I'm not familiar with Krynn overly much, but a lot of that world's history lacked clerics too.
The only giant issue you need to answer is about healing from wounds. How is that done? The optional vitality and wounds system from Ultimate Combat, or an equivalent, is recommended if clerics are missing.
And remember, certain creatures are FAR more dangerous if there's no cure for what happens. Even the typical 1st level giant rats are more threatening if filth fever can really kill you.