Uruguay managed just 42 points in the last Rugby World Cup but Aguirre accounted for 17 of them.
Position: Inside centre/fly-half
Team: Carrasco Polo
Past World Cups: 1999
Did you know? Plays club rugby in Spain
His scoring is likely to be lower this time around, having handed over kicking duties to brother Sebastian.
But the Uruguayan captain remains a key cog to the South American team's ambitions.
His versatility is his strongest asset. He has played at fly-half, scrum-half and centre to date in his 50-odd appearances.
And wherever coach and former captain Diego Ormaechea opts to play him this time around, he looks set to play another crucial role in his second World Cup.