You can't really do this for sports betting:
For poker all-ins you can calculate the probability of each outcome (almost) exactly (ie: you have to assume the remaining deck is distributed uniformly; when actually it won't be because of the folded-out players' strategies biasing the deck in favour of smaller cards, etc).
The best you can do for sports betting is assume that either your own odds (ie: if you have created your own "tissue"), or the public's odds, are close enough and use them in place of the actual outcome probabilities.
Alternatively, you can use
bootstrapping, but if you bet at very disparate odds (eg: betting outsiders in non-handicap horse races, etc) you'll need a fairly long history of bets for this work properly.
Juk