It either is or is not rental property. The only way to exclude it would be to let it for less than 15 days. In that case, you do not report the income in any way.

There's a special rule if you use a dwelling unit as a residence and rent it for fewer than 15 days. In this case, don't report any of the rental income and don't deduct any expenses as rental expenses. Tax Topic 415

If the property is rented out for less than 15 days total during the tax year, you don't report anything at all concerning it, on your tax return. Otherwise, it "is" rental property.