Chelsea will return to Everton with a fourth and final offer for John Stones potentially worth £40m after the England international submitted a formal transfer request.

Stones, who has four caps and will be included in Roy Hodgson’s squad for next month’s Euro 2016 qualifiers against San Marino and Switzerland, has made an impressive start to the season, which has served to fuel Chelsea’s desire to prise him from Goodison Park. Offers worth £20m and £26m have been flatly rejected by Everton since mid-July, with a third of around £30m also knocked back last week.

On each occasion Everton had made clear to Chelsea they had no intention of even entering into negotiations over the centre-half, who has four years remaining on his contract. Yet the 21-year-old privately informed Roberto Martínez last week that his preference is to move to Chelsea.

He had been reluctant to force the issue further but Everton’s refusal to countenance his departure this summer has prompted Stones to take matters into his own hands. The appeal of Champions League football with the Premier League title holders is apparently too great and Stones handed in the request before training on Tuesday afternoon and is now awaiting a response.

Everton have suggested publicly that their hardline stance would not change even if the player asked for a move, maintaining a policy that saw them retain Leighton Baines despite strong interest from Manchester United in 2013. The left-back opted against submitting a transfer request and, six months later, signed a long-term contract at Goodison Park.

Yet Stones has decided against following his team-mate’s lead and has risked the wrath of supporters by asking to go, leaving the chairman, Bill Kenwright, and Martínez with an awkward decision to make. While their instinct will be to reject the request, they now have an unhappy player on their books and will be acutely aware that only a small window remains for them to secure a replacement before Tuesday’s transfer deadline.

If Stones does leave, Everton would be left with only one senior centre-half, England’s Phil Jagielka, in their squad, with less than a week to recruit.

Chelsea’s fourth offer is likely to total around £35m with add-ons to take it to £40m – double their initial valuation of the defender – with the manager, José Mourinho, convinced Stones would represent both a long-term asset and a player who could be flung straight into his first team.

Mourinho has seen John Terry struggle to date this season, despite playing every minute of the club’s title-winning campaign, with the captain substituted in the defeat at Manchester City and sent off at West Bromwich Albion last Sunday. Another senior player, Branislav Ivanovic, has endured a torrid first few appearances at right-back, a position Stones has filled in at for club and country.

If the player does force through a move then his former club, Barnsley, will be entitled to a significant cut – understood to be 15% – of the fee under the terms of the deal negotiated when selling him to Everton in January 2013 for an initial £1.25m, potentially rising to £3m with add-ons.

Everton, who play Chelsea at Goodison immediately after next month’s international break, visit Oakwell on Wednesday for a League Cup second round tie in which Stones was expected to feature, though it remains to be seen whether he will now be involved.

Chelsea, who signed Pedro from Barcelona last week for £21.2m, may seek to undertake more business before the deadline and retain an interest in the Juventus midfielder, Paul Pogba, though it appears any deal for the France international, which would cost up to £70m to complete, is unlikely to be concluded in the window. Victor Moses, who has been suffering with a groin injury, is interesting West Ham United and could yet be permitted to move.

Juan Cuadrado, a £23.3m arrival from Fiorentina in January, has departed Stamford Bridge for Juventus on a season-long loan while Marko Marin has become the 26th player to leave Chelsea on a temporary deal this summer after moving to the Turkish club, Trabzonspor. There is an option for the Germany winger to make the move permanent for around £2.9m next summer.