Melbourne, Dec 30 : The England cricket team will have to play the fourth Test in Sydney without head coach Chris Silverwood after he was forced to isolate for 10 days as a close contact of a person testing positive for Covid-19. Silverwood must isolate after a family member as part of England's touring party in Australia tested Covid positive, the BBC reported on Thursday. The fourth Ashes Test starts in Sydney next Wednesday (January 5). England have already lost the Ashes after their defeat in the third Test here and Silverwood's absence is a big setback for the team ahead of the next match. England have recorded seven positive cases -- three support staff and four family members since a PCR testing regime began on Monday (December 27), the report said adding that the three coaches who have tested positive are fast bowling coach Jon Lewis, spin bowling coach Jeetan Patel and strength and conditioning expert Darren Vendess. "Following the latest round of PCR tests administered to the Eng'and Men's touring party on Wednesday, one family member has tested positive," the England and Wales Cricket Board (ECB) said in a statement on Thursday. "As a result of the positive test, England Men's Head Coach Chris Silverwood will have to isolate for 10 days, along with his family, in Melbourne and will miss the fourth Ashes Test due to start in Sydney on Wednesday, January 5, 2022," the ECB said. England will have the fourth round of PCR tests on Thursday. Both teams -- England and Australia -- are due to fly to Sydney via a chartered flight on Friday morning. /IANS