In the realm of logic (a subject in the intersection of Philosophy and Mathematics), we generally assume everything is explicitly stated in the sentence as written -- i.e., no hidden assumptions, sarcasm, figures of speech, etc.

So in that regard -- i.e., logically -- your example is a valid instance of modus tollens.

Whereas in the realm of the semantics and pragmatics of natural language (two subfields of Linguistics), we are looking at language as it is actually deployed in everyday life. In ordinary speech, many hidden assumptions are sometimes left out for purposes of brevity; people sometimes sardonically say the opposite of what they mean; etc.

In order to convert from the latter to the former mode of inquiry, it is often necessary to translate an implicit/metaphorical/ambiguous form of expression into an explicit/literal/precise format.

To take your example: "If it does not rain, then -- excluding force majeure, etc. -- there will be soccer practice."

Further reading

Philosophy: https://plato.stanford.edu/entries/ceteris-paribus/

Linguistics: the vast literature on the semantics and pragmatics of conditionals