The Blues have won just one of their last seven Premier League games, leaving them fifth in the table, 15 points behind leaders Arsenal.
After the last match against Bournemouth on December 30, which ended in a 2-2 draw, assistant manager Willy Caballero said Maresca was not well enough to speak to the media.
However, his absence was said to be due to serious considerations regarding the future of his career.
There are reports that Chelsea held a board meeting on New Year's Day to discuss the situation.
Despite their dip in league form, Chelsea have reached the semi-finals of the League Cup, are still in the Champions League race, and will face Charlton in the third round of the FA Cup.
