Complex sentence: Due to a controversial blood substitution by Offaly against Kildare, the tie's participants were decided on an appeal of the GAA's decision to let Offaly continue in the Leinster Championship, once it was clarified that they hadn't broken the substitution rules.
Split into simpler sentences: Due to a controversial blood substitution by Offaly against Kildare, the tie's participants were decided on an appeal of the GAA's decision to let Offaly continue in the Leinster Championship. Eventually it was clarified that they hadn't broken the substitution rules.