Diego Costa saga, Chelsea's depth issues have Antonio Conte frustrated
Chelsea are reigning Premier League champions, but listen to Antonio Conte speak and you wouldn't know it. The notoriously intense Italian looks frustrated and worn down, the opposite of refreshed after a summer that has prompted more grimaces than smiles at Stamford Bridge.
ESPN FC runs through the five main reasons why Conte is less than satisfied.
The Costa Mess
Chelsea always knew they would face a big decision on Diego Costa's future this summer. He has never extended the contract he signed on arrival from Atletico Madrid in July 2014 -- it now has just two years left to run -- while repeatedly agitating for a return to the Spanish capital.
Few, however, would have predicted the ugly public standoff that has marred Chelsea's summer and grows more toxic by the week.
Conte's decision to tell Costa by text that he was no longer wanted at Stamford Bridge looks likely to prove a costly mistake, even if Chelsea's position is that the striker knew in January that he would be leaving after the training-ground row sparked by Tianjin Quanjian's interest.
Costa is now more determined than ever to force through a move to Atletico, who know the pressure on Chelsea to cut loose of their unsettled striker will only grow with every new day he spends in exile. As long as he remains on the books, he is an unwanted distraction for Conte.
Conte made clear in May that Chelsea would need quantity as well as quality if they were to return to the Champions League as genuine contenders. In a hyper-inflated transfer market that has tested the patience and resolve of all top clubs, their setbacks have outweighed their successes.
Some of Conte's requested targets -- most notably Leonardo Bonucci -- were dismissed by the Chelsea hierarchy for being too old. Others, such as Alex Sandro and Virgil van Dijk, remain tightly in the grip of clubs with no need or desire to sell at any price.
Meanwhile, players deemed expendable to Chelsea's immediate trophy charge by Conte have either been sold (Nemanja Matic, Nathaniel Chalobah, Nathan Ake) or loaned out (Ruben Loftus-Cheek, Kurt Zouma). But replacements have not yet arrived, stretching an already thin squad to the breaking point.
The four new signings Conte has been given are well-regarded, and hopes are high that returning academy graduate Andreas Christensen can build upon the rich promise shown in two years on loan at Borussia Monchengladbach.
But it's clear that the final weeks of the transfer window are crucial. Chelsea expect to make up to four more signings to provide much-needed cover, particularly in the midfield and wing-back positions. If they don't, the tension between Conte and his employers will reach a whole new level.
The strength of Chelsea's rivals
Conte will not have enjoyed Matic's flawless Manchester United debut against West Ham on Sunday. Aside from Chelsea's own problems in central midfield, the Serb appears to have given Jose Mourinho's side the defensive balance that all Premier League title winners need.
It says something, then, that United are still not favourites. On the other side of Manchester, Pep Guardiola has acquired the dynamic full-backs so noticeably missing from his Manchester City team last season as well as amassing the most formidable array of attacking talent ever seen in the Premier League.
Tottenham's best starting XI remains arguably the most complete team in the country, while Arsenal and Liverpool will both enter September considerably enhanced if they stand as firm as they have pledged to on Alexis Sanchez and Philippe Coutinho, respectively.
The Premier League's top six is a less-forgiving mini-league than ever and just underneath it, Everton have responded to losing Romelu Lukaku with the biggest spending spree in their history.
Chelsea, without Costa and lacking a bench, are undeniably weaker. Winning the title from here would be Conte's most impressive achievement yet.
Conte's quip after the Burnley loss that he would have to research 10-man formations was widely interpreted as a thinly-veiled dig at referee Craig Pawson, who was booed off Stamford Bridge at the end of both halves of action.
But whatever other intent behind Conte's words, they were primarily a message to his players. Chelsea have now incurred four red cards in their past three official matches -- two for dangerous tackles and two for an accumulation of avoidable minor infractions.
Dismissals for Gary Cahill and Cesc Fabregas against Burnley were particularly brainless, and the subsequent suspensions make Chelsea's task against Tottenham at Wembley this Sunday even harder. With the stakes this high, Conte will not tolerate further moments of madness on the pitch.
Pictures that emerged this week of Eden Hazard and Tiemoue Bakayoko back in full training and participating in a behind-closed-doors friendly against QPR provided a timely boost for Conte, whose early-season problems have been compounded by the absence of his best player and marquee midfield signing.
Neither are expected to feature against Tottenham, though Bakayoko is considered closer to a return than Hazard. Both men missed the entirety of Chelsea's preseason, when Conte takes pride in drilling his players to peak levels of conditioning.
Pedro Rodriguez, already playing with a protective mask, missed the Burnley game with an ankle knock and is battling to be available to face Spurs. With so few other established options on the edge of his starting XI, Conte could really do with a swift change of injury luck.
Liam is ESPN FC's Chelsea correspondent. Follow him on Twitter: @Liam_Twomey.