The reserve rower replaced the starter in Tokyo itself due to a case of Covid:
https://en.m.wikipedia.org/wiki/Rowing_at_the_2020_Summer_Olympics_–_Men's_coxless_four
I used to think that it was about too little money that the Italian Olympic Committee invests in rowing and that is why it is more profitable for some athletes to go to study in the USA and work there, instead of continuing their sports career in Italy. In the UK or the Netherlands, I haven't heard of any cases where someone went to study during the four-year period between the Games, or maybe I'm wrong? What's more, when I look at the Romanian team led by Italian coaches, I see greater stability and continuity in the squads there than in our country. In addition, Romania trains most of the time in Italy. I don't know what the problem is, but the frequent departures to study in the USA - mainly women - and the constant injuries are strange. Perhaps we should follow the example of Romania, which is not as rich a country as the UK, the Netherlands or Germany, but has great results in rowing. Maybe we should bring those coaches back to Italy and let them build such a system here? But it definitely invests more money.