Manchester City were working on a deal to sign Bernd Leno from Bayer Leverkusen before landing Ederson.
Pep Guardiola had both goalkeepers watched extensively during his first season in charge upon realising Claudio Bravo's move from Barcelona was doomed.
City plumped for Benfica's Ederson, making him the second most expensive goalkeeper in history at £35million, and now believe the Brazil international is worth double that amount.Leno, meanwhile, went on to seal a £22.5m switch to Arsenal a year later and endured an indifferent first season at the Emirates Stadium.
A new book charting Guardiola's unprecedented success, 'Pep's City: The making of a superteam,' reveals the two-man shortlist to replace Bravo in 2017.
'They both fitted the bill,' sporting director Txiki Begiristain said.
'One was more expensive to buy, the other required a higher salary.
'I left it up to the coaches to choose.'
Chief executive Ferran Soriano added: '(Ederson is) cheap at the price.'
The 26-year-old is regarded as the Premier League's best goalkeeper in possession, something Guardiola demands of his No 1.
City had set their sights on Barcelona's Marc-Andre ter Stegen before signing Bravo weeks after Guardiola's arrival.
That move broke down amid Barca's reluctance to sell and Manchester University rejecting an application by Ter Stegen's partner to study in the city.