West Ham sacked Slaven Bilic seven days ago, and appointed David Moyes within 24 hours of the Croatian's departure.
But it would appear the Scot was not the only name considered by the Hammers as they weighed up a managerial change.
According to Sport, West Ham made contact with Flores the month before Bilic's sacking, only to be informed the Spaniard had no intention of leaving current employers Espanyol before the end of the campaign.
But with Moyes only on a six-month contract at the London Stadium, a move for Flores - who led Watford to 13th in their first season back in the Premier League - could still happen.
Nevertheless, Sport reports West Ham would still have to pay the release clause in the 52-year-old's contract, or hope that he is a free agent by then.
Flores, who managed Valencia, Benfica and Atletico Madrid before his season in England, is under contract at Espanyol until 2019.