On this page, https://learnenglish.britishcouncil.org/english-grammar-reference/verbs-in-time-clauses-and-if-clauses, there is a section called "Making hypotheses" It says: some conditional clauses are like hypotheses, so we use past tense forms. We use past tense forms to talk about something that does not happen or is not happening in the present. One of the examples from that section is given below:
If Jack was playing, they would probably win.
The tense in this sentence confuses me. If I were to rewrite it, I would say, "If Jack was playing, they could/would have probably won. Shouldn't we use the past modal could have/would have here? I am also not sure, whether "could have" or "would have" should be used. As it is a result of the past unreal condition that we are talking about, my choice would be - would have. Could have also sounds appropriate because it is about the possibility in the past which didn't happen. Can someone explain to me how to approach this?