The site, unai-emery.com, had a single page with a message that read: "Proud to be part of the Arsenal family," with the manager's signature below and an Arsenal logo above.
Emery is set to be named the next Arsenal boss in the coming days and became available after leaving Paris-Saint Germain at the end of the 2017-18 campaign, having won the Ligue 1 title, two Coupes de France, two Coupes de la Ligue and two French Supercups during his two seasons in charge there.
The 46-year-old is expected to sign a two-year deal at the Emirates Stadium with an option for one additional season.
The Spaniard, who previously worked at Sevilla, where he won three consecutive Europa League titles, and Valencia, carved out a reputation for fluid, attacking football with the Spanish sides.
The image was down from Emery's site in short order, making it likely that the graphic was pushed live either by accident or ahead of schedule, but is shown in the screenshot below.
While Arsenal say there are no plans for an immediate announcement, it is still expected that the club could make their move to hire Emery official as early as Wednesday.
The Gunners parted ways with long-time manager Arsene Wenger at the close of the 2017-18 season.
Emery will be tasked with leading the Gunners back into contention at the top of the Premier League table, with Wenger's side having dropped out of the top four in the last two seasons after 19 straight years of Champions League football.