Costa has not played for Chelsea since the FA Cup final in May, following which he claims manager Antonio Conte sent him a text telling him he was not in his plans for the new season.
'We want to thank him (Costa) for what he did with this club. We wish him all the best for the future'
Salomon Kalou and Jose Bosingwa, who featured in Chelsea's Champions League final win over Bayern Munich in May, have left the London club.
Middlesbrough handed Chelsea only their second Premier League defeat this season with a 3-0 victory.
Chelsea have made a promising start to a new Premier League season but manager Antonio Conte wants the players to remember the difficulties of last season and learn from that experience.
Chelsea's stuttering form continued on Saturday when the Premier League leaders kicked off a hectic holiday programme with a 0-0 draw at Birmingham City.
A 1-0 victory in the second leg semi-final gave Liverpool a place in the Champions League final.
Although Chelsea's two championships have come 50 years apart, it is highly unlikely they will need to wait another half-century for a third.
Chelsea have followed up the dismissal of manager Avram Grant by sacking his assistant Henk ten Cate, the Premier League club said on their Web site on Thursday. Ten Cate left his job as coach of Ajax Amsterdam to join Chelsea in October 2007 as assistant to Grant.
Eden Hazard scored from the spot in stoppage time to salvage a 2-2 draw for Chelsea against West Bromwich Albion, who were seconds away from inflicting a first Premier League home defeat on a Chelsea side managed by Jose Mourinho.
Former Chelsea and England midfielder Frank Lampard announced his retirement from professional soccer on Thursday after spending last year with New York City in Major League Soccer in the United States.
Liverpool can eliminate one of their two rivals from the Premier League title race by beating Chelsea on Sunday, and the way the dice is rolling for them they might even have one hand on the trophy by the end of the weekend.
Chelsea rounded off the UEFA Champions League group stage with a 3-1 victory over Sporting.
Ivory Coast striker Didier Drogba is leaving Chelsea after playing a leading role in their Champions League triumph, according to a report to be published in French magazine France Football on Tuesday.
Chelsea were charged by the FA with misconduct for allegedly breaching rules governing private drug testing by the club
Porto defender Jose Bosingwa has agreed a three-year deal with Chelsea and will join the Premier League runners-up after Euro 2008, the club said on Monday. "Jose Bosingwa has agreed terms with Chelsea Football Club. He has agreed a three-year contract," said a statement on the club's Web site (www.chelseafc.com).
Chelsea reclaimed top spot in the Premier League with a crushing 5-0 win over Blackburn Rovers on Saturday but Tottenham Hotspur were brought down to earth when Stoke City snatched a late 1-0 victory at White Hart Lane.
Chelsea captain John Terry went from zero to hero, first netting an own goal but eventually coming up with a 98th minute equaliser in an extraordinary 3-3 draw with Everton in the Premier League on Saturday. Manager Guus Hiddink's unbeaten record survived after an amazing match that saw his side fall two goals behind soon after halftime, fight back to 2-2 and then seemingly throw away the points with poor defending which saw Everton sub Ramiro Funes Mori score in the 90th minute.
Liverpool opened up a seven-point gap at the top of the English Premier League with a 1-0 win at Brighton & Hove Albion on Saturday, while Arsenal's poor away form continued with a 1-0 defeat at West Ham United.
The hosts struggled to break down Arsene Wenger's side despite enjoying the majority of possession and will feel hard done by after crafting the best of the game's few openings in a lively game at Stamford Bridge.
The English Premier League matches are on. Are you cheering for Chelsea? Or Manchester United?
Premier League champions Chelsea eased past a disappointing Everton with goals from Spaniards Cesc Fabregas and Alvaro Morata sealing a 2-0 victory on Sunday.
Chelsea must end their hire-and-fire approach and make sure the club's next manager is a long-term appointment, interim boss Guus Hiddink said on Friday. The Dutchman has overseen a dramatic turnaround in fortunes, helping the champions climb to 10th in the Premier League after they were struggling one point off the relegation zone when he replaced the sacked Jose Mourinho in December. Chelsea have changed their manager 10 times since Russian billionaire Roman Abramovich became owner 13 years ago with 2005, 2006 and 2015 league winner Mourinho serving two spells at the helm and Hiddink twice operating in an interim role. "The club has to go in a new way where it is not on short spells," Hiddink told a news conference ahead of Saturday's game against seventh-placed Stoke City at Stamford Bridge. "I think now they have to go into a new era of Chelsea where managers have more than one or two years."
Hasselbaink came on to score three times in the last 15 minutes in a 5-2 rout over Wolverhampton Wanderers.\n\n
New Chelsea manager Antonio Conte has urged his players to retain the aggressiveness they have shown during the pre-season, saying that the combative nature of the game was essential to the style of play he is looking to impose at the club. Six players were booked, while midfielder Cesc Fabregas was shown a red card, in Chelsea's feisty 1-0 victory over Liverpool on Thursday after Gary Cahill's early header condemned the Merseyside club to their first pre-season defeat.
John Terry made an emotional address to his devoted Chelsea fans on the Stamford Bridge pitch on Sunday, telling them that he still wanted to stay at the club.
Schwarzer, 42, played 12 times for Chelsea last season as backup to Petr Cech, but has only been an unused substitute four times this season.
The EPL champions, Jose Mourinho and Ashley Cole were found guilty of breaking contract rules by the governing body.
The new English season got off to a familiar start as two Sergio Aguero goals, including his 200th for the club, handed Manchester City a 2-0 win over Chelsea and claim the FA Community Shield for the fifth time at a sun-baked Wembley.
Chelsea defender Branislav Ivanovic has been charged with violent conduct by the Football Association for an incident in the game against Wigan Athletic at the weekend, the FA said in a statement on Tuesday.
Jose Mourinho left Stamford Bridge because his relationship with Chelsea had broken down and the effects could be seen in their results, the Premier League club said.
Robin Van Persie scored a dramatic stoppage time equaliser to earn Manchester United a deserved 1-1 draw at home to Premier League leaders Chelsea on Sunday.
Chelsea defender Cesar Azpilicueta has signed a new three-and-a-half-year contract that runs until 2020, the Premier League club said on their website on Tuesday. The versatile 27-year-old has been a regular starter since joining the London side in 2012 and is set to make his 200th appearance for the league leaders if selected for Wednesday's game at Sunderland.
Rattled by embarrassing domestic defeats, Chelsea looked jittery before Olivier Giroud settled their nerves with a close range tap-in shortly after halftime at StamfordBridge following good work by N'Golo Kante and Willian in the build-up.
The Premier League champions signed Athletic Bilbao left back Asier del Horno for $14.50 million on a three-year contract.
Portuguese club Sporting Lisbon are to complain to FIFA after three of their development squad players trained with Chelsea.
Chelsea's Brazil playmaker Oscar was taken to hospital after being clattered by Arsenal goalkeeper David Ospina during the 0-0 Premier League draw at the Emirates on Sunday.
