The Blues have confirmed they have signed the FC Basel winger, subject to the agreement of personal terms and pending a medical, as Juan Mata prepares to join Manchester United.
The Blues have revealed that an agreement has been reached between themselves and the Swiss Super League side for the transfer of the Egypt international, subject to personal terms and pending a medical.
Liverpool had been strongly linked with Salah but as Goal reported on Wednesday night, Chelsea views the wide man as a direct replacement for Juan Mata, who is expected to join Manchester United in a £37 million deal.
Mata, who has made just one appearance for the Blues since December 29, flew in to United's Carrington training base by earlier on Thursday as he underwent a medical at the club's new health-care facility.
Salah, meanwhile, has faced Chelsea four times in the past two seasons, scoring three times against the Blues and has racked up 78 appearances and 20 goals for Basel since signing from Al Mokawloon in 2012.