Tomas Kalas
Tomas Kalas joined Chelsea in January 2011Getty

Chelsea have secured the long-term future of centre-back Tomas Kalas to Stamford Bridge, casting doubt on speculations linking them with a move for Everton starlet John Stones.

Jose Mourinho already has John Terry, Gary Cahill and Kurt Zouma in his central defensive ranks ahead of the new campaign but has earmarked the signing of Stones as a priority to become him into the captain long-term replacement.

The Daily Telegraph recently claimed that the Portuguese boss was considering a £34m ($52.8m) offer to secure the England international defender after Roberto Martinez reacted angrily to the Blues' opening £20m bid.

And even though the pursuit for the Everton prodigy may continue, the Blues have secured Kalas on a long-term deal – just days after sending him on loan to Middlesbrough to continue his development.

"Chelsea Football Club is pleased to announce Tomas Kalas has signed a new three-year contract," the club confirmed in an official statement.

The 22-year-old defender moved to the Chelsea academy in January 2011 from Sigma Olomouc as a hotly tipped prospect.

He spent a season on loan at Vitesse Arnhem before Mourinho handed him his first team debut during a League Cup victory over Arsenal in the 2013-2014 campaign.

During the same season, the defender also enjoyed an impressive league debut alongside Branislav Ivanovic during a 2-0 victory at Liverpool.

But following last summer's arrival of Zouma, Mourinho opted to send the player on loan to Koln for the first part of the 2014-2015 campaign, before the centre-back made the move to Middlesbrough in January.

Just days after securing another loan move to Aitor Karanka's side, the Blues have opted to commit his future to the club in a sign Mourinho still sees Kalas's future at Stamford Bridge.