Chelsea are reportedly concerned they won't be able to sell Diego Costa during this transfer window because the striker is no longer in peak condition after a lengthy summer break.
Spain international Costa has even opened legal proceedings against the Stamford Bridge side as he tries to force a move back to old club Atletico Madrid, per reports.
Costa wants out of Chelsea and has therefore found himself excluded from training and preseason preparation by manager Antonio Conte, per Neil Ashton and John Hutchinson of The Sun.
However, as Ashton and Hutchinson noted, the Blues have become concerned about Costa's conditioning because of a fear he has indulged in a party lifestyle during his time away:
"The club have resorted to monitoring his antics on Instagram while desperately trying to line up a buyer for the party-loving striker.
"There were even images of Costa riding a jet ski with his dog on social media. Chelsea chiefs believe he is losing fitness—and they are now rapidly running out of time to sell him before the transfer window closes."
This is one more chapter in Costa's increasingly fractious and protracted exit from Chelsea. Worse still for the defending Premier League champions, the striker is said to be taking a legal route in response to the Blues' apparent refusal to sell him to Atletico, as well as Conte's attempts to force the player out.
A report from Sami Mokbel of the Daily Mail revealed the process, prompted by representatives of the disgruntled player, has begun.
The saga between looks set to continue to deteriorate during the remaining days of the summer transfer window. It could prove an unnecessary distraction for a club bidding to avoid another dismal title defence.
Chelsea won the league in 2014/15 but followed that with a 10th-placed finish following the midseason dismissal of then-manager Jose Mourinho.
What is lost in the wait for Costa to quit Chelsea is how valuable he has been during their most recent title triumphs. The 28-year-old has been prolific, scoring 20 goals and providing seven assists last season, per WhoScored.com.
His combination play with winger Eden Hazard proved the catalyst in the final third for Conte's man. The latter has drafted in former Real Madrid and Juventus striker Alvaro Morata to fill the void left by the Costa's absence, while Michy Batshuayi is also available.
However, the Spain international will prove a big miss for the Blues as their latest title defence unfolds.
Conte could also find himself frustrated in his attempts to refresh things at the back, after Valencia revealed there has been no offer from west London for Joao Cancelo.
Los Che CEO Mateu Alemany said "there is no Chelsea offer for Cancelo," per Goal's Joe Wright. Alemany's denial comes after Darren Lewis of the Daily Mirror reported the Blues had "entered the bidding" for the Portugal U21 defender.
Chelsea have been linked with a host of full-backs this summer. Juventus ace Alex Sandro has been a target, per The Times (h/t Alex Wood of the Daily Star).
Cancelo would likely be a cheaper alternative to Sandro or Rose, giving Conte a promising squad option behind Marcos Alonso and Victor Moses.
Improving depth is a concern for the Blues boss with the club back in the UEFA Champions League this season. However, Conte's bigger worry has to be how Costa's acrimonious split from the club will play out and what impact his exit will have on Chelsea's season.