London (AFP) - Veteran Australia fast bowler Ryan Harris announced his retirement from all forms of cricket on Saturday, just four days before the start of the Ashes.The 35-year-old had been left out of Australia's final warm-up match against Essex after suffering a recurrence of the knee trouble that has plagued his career.Scans revealed that his right knee had suffered more damage."Given the news I received yesterday, and after talking it over with my family, I know now is the right is the time to step away from cricket," Harris said.Cricket Australia said that 22-year-old Pat Cummins has been called up to replace Harris ahead of the first Ashes Test which gets underway in Cardiff on Wednesday.Harris took 113 wickets in 27 Tests after only making his debut in 2010 at the age of 30.His best figures were 7-117 against England at Chester-le-Street in 2013.