The phrase "a sort of substitute" is correct and usable in written English.
It can be used when describing something that serves as an alternative or replacement for something else, often in a vague or non-specific manner.
Example: "In the absence of fresh herbs, dried ones can be a sort of substitute in many recipes."
Alternatives: "a kind of replacement" or "a type of alternative."
Subsequently, he was bemused to find himself being consulted as an agony uncle by American students, as a sort of substitute for CS Lewis.
On one hand, mobile Internet access was a sort of substitute for travel because many tasks could be completed online instead of by physical movement, such as collecting information about jobs and commodities.
Down to Westminster, another surprisingly well-dressed lady in her mid-40s – honestly, she looks like she could've been one of Lord Sugar's assistant on The Apprentice, a sort of substitute Karen Brady – waves a home made sign and calls us all "traitors"; a man in the high tower of a tall ship gives us a distant thumbs down.
In this way, music acts as a sort of cathartic substitute for real sadness.
"Perhaps his trip to Europe should be seen as a sort of a substitute," Mr. Fewsmith said.
College football, more even than the NFL, functions as a sort of sad-parody substitute for politics in much of the country.
There is also warrant for the worries about unprincipled interpretation, as well as about the reduction of philosophy to a sort of literary sensibility substituting for genuine philosophical argument (where, after all, are Strauss's arguments for any philosophical position, whether or not about a Platonic "teaching"?).
Environmentalists tout a sort-of pagan eschatology.
Wyclif's last formulation of the theory of difference and his theory of universals and predication are linked together, and rest upon a sort of componential analysis where things substitute for lexemes and ontological properties substitute for semantic features.
Another interesting aspect is using of the selected phage itself as a probe in detector devices, like sort of substitute antibodies.
