Clattenburg has returned to training with the top-flight Select Group of referees for the first time since Chelsea's complaint against the match official.
The 37-year-old will miss a third weekend of Premier League matches but the outcome of the Football Association's investigation into Chelsea's complaint of inappropriate language should be known by the end of the week.
Chelsea have alleged that Clattenburg used a term understood to have been interpreted as racist towards Mikel during the Premier League match against Manchester United on October 28. The official strenuously denies having done so.
Clattenburg and referees chief Mike Riley have decided jointly that he should not be in charge of matches while the case has been ongoing. A police investigation has also been taking place following a complaint made on the basis of reports.
Clattenburg had not even trained while the investigations have been taking place but he did so on Monday at St George's Park.
All the interviews with the FA and police have been concluded and the regulatory body of the FA will be advised by an independent QC about whether any action should follow. That decision looks likely to be made before the end of the week.
The governing body have spoken to Clattenburg, assistant referees Michael McDonough and Simon Long and fourth official Michael Jones.
It is believed all the other officials, who were wired up together with Clattenburg, have said they did not hear any use of the term alleged by Chelsea.
The FA are also keen to have a swift conclusion to the case which could not be more sensitive given the recent four-match ban handed to Chelsea's captain John Terry for racist abuse.
- Sports & Recreation