Chelsea have reacted to their worst start for 17 years by submitting a third bid, now of £30m, to Everton for the England defender John Stones, though the proposed deal is still unlikely to secure the player.

The champions have failed with two offers worth £20m and £26m for Stones, who has been capped four times, with Everton infuriated by the pursuit and adamant the defender will not be sold this summer. The third offer follows José Mourinho having substituted his captain, John Terry, at half-time during the 3-0 defeat at Manchester City on Sunday in what has been perceived as a message to the hierarchy that defensive reinforcements are urgently required.

Yet, while Chelsea had hoped the improved offer would at least prompt Everton to come to the table, they are likely to discover Stones’s price has risen given that their defeat at the Etihad Stadium has served to illustrate an increasing need for new faces. Everton are expected to reject the offer for the 21-year-old, leaving Chelsea, who have already seen the bidding process escalate well away from their original valuation, to consider their next move.

Roman Abramovich has indicated he is prepared to re-enter the transfer market. Mourinho has voiced his frustration at Chelsea’s inability, as yet, to build on the title-winning squad. The manager had made great play towards the end of last season that new players would be required to reinvigorate the squad but, while a number of young players have departed on loan, Chelsea have replaced only those senior figures who have left, with Radamel Falcao, Baba Rahman and Asmir Begovic coming in for Didier Drogba, Filipe Luís and Petr Cech. Mourinho indicated last Friday he was confident there would still be “one or two” new arrivals, though that urgency has since been heightened by a defeat which left his side already trailing last year’s runners-up by five points just eight days into the new campaign.

Mourinho, who had been just as unimpressed with his team’s defensive display against Swansea City on the opening day, believes Stones is a long-term solution but could also make an immediate impact, a conviction that may prompt a fourth bid which could make the youngster the most expensive defender in English football. He would compete for a place both at centre-half and at right-back, where Branislav Ivanovic has struggled in the fledgling campaign to date.

There remains the possibility another forward-thinking player could be added to the side if a suitor can be found for Juan Cuadrado, who has failed as yet to make an impression since moving from Fiorentina in January. Chelsea would have to compete with Manchester United for Barcelona’s Pedro and another of their targets earlier in the summer, Antoine Griezmann, has since signed a new deal at Atlético Madrid.

Terry, who had never been substituted by Mourinho in 177 Premier League games, was replaced by Kurt Zouma at City as the visitors looked to implement a higher defensive line. The 34-year-old, who had played every minute of the team’s title-winning success last season, was disappointed at the decision but is still confident he will be picked to start Sunday’s game at West Bromwich Albion.