Filipe Luis
Despite the departure of Filipe Luis, Chelsea are yet to buy a defender this summerGetty

Chelsea manager Jose Mourinho has admitted concern over the shortage of defenders in his squad, amid the departure of left-back Filipe Luis and the Blues being linked with Everton centre-back John Stones.

With the departure of the Brazil international to Atletico Madrid after less than 12 months at the club, Chelsea currently have just five established first-team defenders in their ranks: Cesar Azpilicueta, Branislav Ivanovic, John Terry, Gary Cahill and Kurt Zouma.

Unsurprisingly, Mourinho has himself confirmed that a new left-back will be brought to Stamford Bridge over the summer to battle Azpilicueta for a place on the team sheet.

Meanwhile, the Mirror has reported that the Blues are set to launch an improved bid in the region of £26m ($40m) for Stones after having had a previous approach rejected out of hand by Everton earlier in the summer.

Chelsea are yet to bolster their defence this summer having only signed hitman Radamel Falcao on loan from Monaco, Stoke City keeper Asmir Begovic and attacking midfielder Nathan – who came in from Atletico Paranaense before moving on loan to Vitesse Arnhem to continue his development.

And speaking ahead of their pre-season clash with Barcelona, Mourinho admitted he will be forced to play his defenders for the whole game, less than a week before the Community Shield encounter with Arsenal on 2 July.

"Defenders I have to give 90 minutes to because at this moment I have only five. Between the five we must have four on the pitch and so for the defenders I have to do it," Mourinho reported to the club's official website after played Ivanovic, Terry and Azpilicueta for the full 90 in the 1-1 draw against PSG.

The Portuguese boss, nevertheless, is happy with his side's performance so far in pre-season, saying that matches against big sides like Paris Saint-Germain and Champions League winners Barcelona will help them prefer for the new campaign.

"It's the best training session we could have. The game against PSGwas a very good one; against Barcelona it can be an even better one. I'm not worried with tactical aspects, and I'm not worried with the result. I'm just worried about the possibility to play at a higher intensity and prepare ourselves for the Premier League," the boss added after the Blues secured a 1-1 draw against the Ligue 1 side.

"I need to give players minutes. I need to give players different experiences, playing with each other and also playing in different positions. It's just about preparation. Obviously nobody likes to lose even in training but if we wanted to win we would choose opponents where we could win easily.

"This time, because we have a short pre-season and not a long time to be ready for the Premier League, we decided to play proper opponents and have proper training matches to raise the level."