Jose Mourinho is to be the subject of individual legal action from former Chelsea team doctor Eva Carneiro.
It means the Chelsea boss will have to appear at an employment tribunal unless there is an out of court settlement.
Carneiro was dropped from first-team duties after Mourinho said she was "naive" for treating Eden Hazard during a draw with Swansea.
Her lawyers are already suing the club for constructive dismissal.
The legal papers are expected to be served on Mourinho this week as part of separate, but connected, claims against him and against the club.
The doctor's lawyers said neither she nor they could comment as the legal proceedings are active, while Chelsea have also not commented on the case.
The individual legal claim against Mourinho of victimisation and discrimination means Carneiro's lawyers are alleging he was instrumental in Carneiro's apparent demotion.
The incident in question occurred on 8 August, the opening day of the Premier League season, when Carneiro and head physio Jon Fearn were called on to the pitch during Chelsea's 2-2 draw with Swansea to treat midfielder Hazard.
Chelsea were already down to 10 men after goalkeeper Thibaut Courtois was sent off, and with Hazard having to leave the field after being treated despite appearing not to be badly injured, the team were temporarily reduced to nine men.
Mourinho was widely criticised for his comments but was cleared of using discriminatory language by the Football Association.
Carneiro revealed she had not been spoken to personally during the investigation, nor asked to provide any statement, however, the FA said she was given an opportunity.
The handling of the case has also been criticised by the Women in Football network group and FA independent director Heather Rabbatts.
The FA's chief executive Martin Glenn and head of governance Darren Bailey are to be questioned about the handling of the case by the governing body's Inclusion Advisory Board later this month.
The IAB's chair Heather Rabbatts is also under investigation by the FA for her comments.
Mourinho has come under increasing pressure on the pitch this season, with the reigning champions 15th in the Premier League table having lost six out of 11 matches.
|How the Chelsea row unfolded|
|8 August: Mourinho accuses Carneiro of "naivety"|
|22 September: Chelsea doctor Carneiro leaves club|
|30 September: Mourinho cleared by FA over Carneiro|
|30 September: FA's Mourinho verdict 'appalling', say group|
|1 October: FA boss Dyke criticises Mourinho|