Speaking after a second successive goalless defeat, a 2-0 loss at Newcastle, the Spurs boss said the trio's determination to force moves has become impossible to ignore.
"He said too many times he wanted to leave. Danso came two days ago and said he wants to leave," De Zerbi said of Richarlison, before turning to the other two departures in waiting.
"Sarr is the same. He suffered a small injury but is almost ready to train."
Richarlison, who has a year left on his contract, is attracting interest from former club Everton, while Tottenham are believed to want around £20m to let Sarr go - a fee that makes his exit before the deadline look close to certain. Danso's situation has already been covered in these pages, with Sunderland among the clubs previously linked to the Austria international.
De Zerbi was candid about the scale of the rebuilding job still ahead of him, despite a summer in which the club has spent roughly £300m on new arrivals.
"You can't buy mentality. Football is like a magic thing. You can change many players in one window and find the balance immediately or you need more time," he said. "I would like to do it quickly, as soon as possible.
"The plan, the project of the club and what we are doing is to rebuild a new team with new players."
The comments underline the scale of the reshaping still under way at Tottenham, who have started the campaign with back-to-back defeats and no goals scored despite the outlay in the transfer market.
With Richarlison, Danso and Sarr all pushing to leave, De Zerbi faces the prospect of trimming his squad further even as he searches for a first win of the season.
Richarlison joined Spurs from Everton for a fee that could rise to £60m back in 2022 and has since become Tottenham's top scorer in all competitions last season, netting 11 in the Premier League alone, but has struggled for consistent minutes over the past two seasons and made clear his frustration well before this weekend's admission from his manager.
Sarr, meanwhile, has been a regular fixture in De Zerbi's midfield since joining from Metz, and his likely departure for a fee in the region of £20m would represent a significant reshuffle of Tottenham's engine room just days after the club completed the signings of Sandro Tonali and Mateus Fernandes for a combined £185m.