Aguero has worn the No 10 at City since 2015 but the number is heavily associated with Messi, who has worn it for Barcelona since 2008, while he also wears it for Argentina.
According to reports from RAC1 and TyC Sports, Messi’s father Jorge has arrived in Manchester to hold talks over a possible move.
Messi, frustrated after Barcelona failed to win a trophy this season, believes that he can activate a clause that would make him a free agent at the conclusion of a campaign.
Barcelona, however, state that the clause expired in June, and say that Messi’s release clause of £630million would have to be paid for him to secure a move elsewhere.
In addition to Aguero, Messi has a strong connection with City manager Pep Guardiola, with whom he enjoyed much success in Barcelona.
City fans took to Twitter to state their belief that Aguero’s activity on Instagram means a deal for Messi is likely to happen.
One wrote: ‘Sergio Aguero just changed his Instagram username from “kunaguero10” to “kunaguero”. Omg I can’t believe my eyes right now.’
Another added: ‘SERGIO AGUERO REMOVED 10 FROM HIS INSTAGRAM USERNAME, LAWD it’s REALLY HAPPENING.’
Meanwhile, another Twitter user wrote: ‘Kun Aguero changing his Instagram username from kunaguero10 to kunaguero. Hmmm! what could that mean?.’
Barcelona supporters also commented on Aguero’s actions.
One wrote: ‘Aguero removes “10” from his Instagram username! It’s happening.’
Another added: ‘Aguero has changed his username from KUNAGUERO10 to KUNAGUERO on Instagram. It’s done y’all. Lionel Andres Messi is leaving to Manchester city under pep.’