Chelsea have the funds to put in a tempting bid to City for Aguero and to offer the striker attractive terms, while they may feel their status as Premier League champions could prove valuable in negotiations.
Antonio Conte is on the lookout for a star striker this summer with Diego Costa heading for the exit.
Sky sources say "it will be very hard for Chelsea to sign Aguero" but that their interest is real.
In a shock move, it appears a Sergio Aguero Chelsea transfer has been approved by Manchester City manager Pep Guardiola.
Aguero has fallen down the pecking order at The Etihad since the arrival of Gabriel Jesus. Add in the fact that Manchester City do not have a suitable replacement, and it is hard to think that an Aguero Chelsea transfer is on the horizon.
Arsenal are adamant that they will not sell their attacker to a Premier League rival, but a fee of around £80m could test the club's resolve with Sanchez only having a year left on his contract.