Diego Costa is behind schedule in his bid to start Chelsea's season after suffering a setback in training.

Chelsea's first choice striker has suffered from a minor back problem for the past few days and has not been able to train fully with the squad for the whole of the sessions.

The 27-year-old striker missed the friendly against Liverpool in midweek and is not expected to feature against Real Madrid in Michigan on Saturday.

Chelsea's opening League game at home to West Ham is just over two weeks away, but new manager Antonio Conte admits no player can be considered for selection if they're not taking a full part in the sessions.

He said: “It’s important to see the players doing the training session. If I don’t see a player doing the training session I can’t put them in the game. These are my rules and it’s important to understand this.

“My concept is very clear. I want to see my players doing the work in the training session.

"If someone is injured or there is some problem and I don’t see the player in the training session it is impossible to think of putting him in the starting 11 or on the bench.

“In the last few days he had a pain in the back and for this reason he didn’t train and didn’t play.

“When Costa trained with us I saw always the right attitude but in these days he didn’t train with us."

Costa's injury problems are a blow to Chelsea with the club struggling to sign a striker in the transfer market.

In Pictures: Chelsea vs Liverpool 9 show all In Pictures: Chelsea vs Liverpool 1/9 Cesc Fabregas is sent off following a challenge on new Liverpool signing Ragnar Klavan. Andrew Powell/Liverpool FC via Getty Images 2/9 Gary Cahill heads Chelsea in front after 10 minutes. Jeff Gross/Getty Images 3/9 New Chelsea boss Antonio Conte delivers instructions from the touchline. Andrew Powell/Liverpool FC via Getty Images 4/9 Willian tries his luck from a set piece. Andrew Powell/Liverpool FC via Getty Images 5/9 Cahill receives one of the games many yellow cards following a challenge on Connor Randall. Andrew Powell/Liverpool FC via Getty Images 6/9 John Terry expertly times a challenge to intercept Saido Mane. Andrew Powell/Liverpool FC via Getty Images 7/9 Cesar Azpilicueta, like the rest of Chelsea's back-four, played the full 90 minutes. Andrew Powell/Liverpool FC via Getty Images 8/9 Victor Moses jinks past Marko Grujic. Andrew Powell/Liverpool FC via Getty Images 9/9 Chelsea mascot, Stamford the Lion, proved unsuccessful in his attempts to win the hearts of the Livepool fans... Andrew Powell/Liverpool FC via Getty Images 1/9 Cesc Fabregas is sent off following a challenge on new Liverpool signing Ragnar Klavan. Andrew Powell/Liverpool FC via Getty Images 2/9 Gary Cahill heads Chelsea in front after 10 minutes. Jeff Gross/Getty Images 3/9 New Chelsea boss Antonio Conte delivers instructions from the touchline. Andrew Powell/Liverpool FC via Getty Images 4/9 Willian tries his luck from a set piece. Andrew Powell/Liverpool FC via Getty Images 5/9 Cahill receives one of the games many yellow cards following a challenge on Connor Randall. Andrew Powell/Liverpool FC via Getty Images 6/9 John Terry expertly times a challenge to intercept Saido Mane. Andrew Powell/Liverpool FC via Getty Images 7/9 Cesar Azpilicueta, like the rest of Chelsea's back-four, played the full 90 minutes. Andrew Powell/Liverpool FC via Getty Images 8/9 Victor Moses jinks past Marko Grujic. Andrew Powell/Liverpool FC via Getty Images 9/9 Chelsea mascot, Stamford the Lion, proved unsuccessful in his attempts to win the hearts of the Livepool fans... Andrew Powell/Liverpool FC via Getty Images

The club's top targets are Alvaro Morata and Romelu Lukaku, but the asking price has been set at £67m and £75m respectively by Real Madrid and Everton.

Costa's absence coincides with Atletico Madrid's continued attempts to re-sign the striker.

Chelsea warned the La Liga club that the Spain international is not for sale earlier this month, but the speculation refuses to go away.

Chelsea do have £33.1m summer signing Michy Batshuayi available, but he is still adjusting to a new club, Conte's tactics and is a newcomer to the Premier League.

The other forwards in the squad in the USA are Loic Remy, youngsters Bertrand Traore and Tammy Abraham, while Ruben Loftus-Cheek has been played in a more advanced role in pre-season.

Meanwhile, Conte has confirmed that Eden Hazard and Thibaut Courtois will make their first appearances of pre-season against the Champions League holders.

The Belgium duo only joined up with the rest of the squad at the start of the week having been given extended time off after Euro 2016.

He added: “Eden will play the second half. We are expecting a time to do the right metabolic work and the right tactical work before we put the players in the game. For Hazard the right moment is in the second half.

"I am happy with the (goalkeeping) situation. In these three games Asmir Begovic showed his strength. Begovic is a good goalkeeper.

"Now Courtois is back and tomorrow we start with Begovic and in the second half we play Courtois."