You don't have to climb Mt Everest to be affected by altitude. Rugby teams suffer too.
However, Tucker points out that there is another school of thought followed by some teams: by minimising 'exposure' in other words arriving at the high altitude only hours before the game, and leaving straight afterwards, the negative impact on performance will be reduced.
Tucker does not subscribe to this, and since there have been no scientific studies to prove that this method actually works, he has science on his side.
Above 2 500m: acclimatisation period of three days strongly recommended;
Above 2 750m: mandatory acclimatisation period of one week;
Above 3 000m: games generally not permitted except with a minimum acclimatisation period of two weeks.