The 'Special One' is interested in adding highly-rated Moroccan international Mehdi Benatia to his squad.
According to The Daily Star, the 27-year-old is also being chased by Manchester United, but Chelsea are ready to seal the deal this week ahead of their first game at Burnley on Monday.
The signing of the French-born player means the Blues will have to sell one of their foreign players, as they will have exceeded their allowed quota under the Premier League rules.
Chelsea host Real Sociedad at Stamford Bridge in their final pre-season friendly tonight.
Mourinho insists his side will then be ready for the big kick-off.
"It's been a difficult pre-season because we started with seven players", he said.
"After that, step by step, players were arriving after the World Cup and holidays.
"For example, Branislav Ivanovic been training for one month, Schurrle has trained for five days, so there is a big difference between players.
"We have to play the first league match next weekend and we will be ready for that."