Atlético Madrid are preparing to table a first formal bid with Chelsea for Diego Costa in the hope they can re-sign the Spain striker before his scheduled return for pre-season training at Cobham at the start of next week.

Costa is technically due to report back to the Premier League champions on Monday despite the fact the manager, Antonio Conte, has made clear the forward is not in his plans for the campaign ahead. The Italian will be back at the club on Sunday, 24 hours before his squad reconvenes for standard medical checks, but he could yet be spared an awkward encounter with Costa should Atlético lodge an offer deemed acceptable for the player.

There were suggestions in Spain on Wednesday night that Costa was only “hours” away from being confirmed as an Atlético player, although that is understood to be optimistic with no fee has, as yet, having been agreed by the clubs and with the move also potentially complicated by Atlético being banned from signing players until January.

The 28-year-old’s insistence he would only leave London to return to Madrid has damaged Chelsea’s hopes of raising the £76m first mentioned when interest was expressed by Chinese Super League clubs back in January. Their asking price is likely to be nearer £40m this time around and, should Atlético offer that much, a deal will be concluded swiftly. If, however, the Spanish club propose an initial fee closer to £22m plus add-ons, an arrangement that has been mooted, then negotiations could prove significantly more protracted and force Costa to return to Surrey to begin fitness work under Conte with his club-mates.

The relationship between striker and manager was fractured beyond repair last month when Conte texted the Spain international to make clear he had no future at Stamford Bridge, with Costa duly making that message public, effectively weakening Chelsea’s negotiating position in the process. The club remain adamant they will not be forced into accepting a deal with which they are dissatisfied, but will only excuse Costa’s absence on Monday if a deal has either been concluded with Atlético, or is in the process of being wrapped up.

The players are due to begin double sessions later next week and will play two friendlies, one behind closed doors, prior to departing on a tour of China and Singapore on 18 July. They play Arsenal, Bayern Munich and Internazionale in the Far East.

Conte will hope his options are significantly bolstered by then, with the club close to announcing the signings of Tiemoué Bakayoko from Monaco and Antonio Rüdiger from Roma. Talks continue with Juventus over Alex Sandro, who would cost a club record £61m, and interest is retained in Everton’s Romelu Lukaku, whom the manager has identified as his preferred replacement for Costa. He could cost as much as £100m.

Only once additions have been made will the futures of Nemanja Matic and Ruben Loftus-Cheek, who are coveted by Manchester United and Newcastle United respectively, become clear.

Chelsea, who have already loaned out their England Under-21 internationals Tammy Abraham and Kasey Palmer to Swansea and Huddersfield, expect to send another of their young talents, Izzy Brown, to newly promoted Brighton & Hove Albion on a similar arrangement. The 20-year-old will put pen to paper on a new long-term deal prior to departing for the Amex Stadium.

Another of the stalwarts of the national team’s Under-21s, the midfielder Nathaniel Chalobah, is seeking more regular involvement in the Premier League having been reduced to only one top-flight start last season. Chelsea would ideally like to secure him to a new five-year deal and then loan him once again, but the 22-year-old may be more inclined to seek a permanent move elsewhere, particularly once Bakayoko, as anticipated, adds to the competition at the club.

Watford, for whom he played in the Championship in 2012/13, have expressed an interest in a player who is entering the final year of his current contract. Chalobah is due to undergo a scan on Thursday on a groin complaint sustained against Germany in the recent semi-final of the Under-21s European Championship, and will meet with Chelsea officials next week to discuss his future.