Leach, who took four wickets in England’s 10-wicket win over Ireland in a one-run test earlier this week, has been a constant presence in the England squad under coach Brandon McCullum and captain Ben Stokes, taking 46 Test wickets last year.
He was included in the 16-man squad for Ash’s first two Tests announced by England on Saturday.
Leach’s injury was the latest major setback for England bowling ahead of the series, as Jofra Archer also dropped out.
The 31-year-old lefty slow player from Somerset developed symptoms in his lower back during England’s win over Ireland on Saturday, the ECB said in a statement.
A scan Sunday in London revealed a stress fracture that will prevent him from taking part in the upcoming Ashes Test series…England will announce a replacement for the Ashes series in due course.
The Ashes series will begin at Edgbaston on June 16.