Overton, who starred with the bat on his Test debut against New Zealand last summer with a match-turning 97, has returned home from the UAE, where he was part of the Gulf Giants squad at the inaugural ILT20 competition.
Although Surrey held back from confirming initial reports about his injury, further investigations have confirmed that he has sustained a stress fracture of the lumbar spine, and will now begin a period of rehabilitation.
With the Ashes taking part in the first half of the English summer - the first Test is due to begin at Edgbaston on June 16 - Overton is almost certain to miss the entire campaign, a significant blow to his ambitions and to England's pace-bowling stocks.
Last season, two other Test debutants, Matt Fisher and Saqib Mahmood, were ruled out of the international summer after suffering stress fractures of the back, as were Olly Stone and Jofra Archer. All four men are now back to action, with Stone and Archer impressing at the SA20, and Fisher and Mahmood due to take part in the forthcoming Lions tour of Sri Lanka.
Overton's injury comes after he was preferred to Matt Potts for the recent tour of Pakistan, in which he was an unused reserve. Potts had already won his place back for the tour of New Zealand in February, with Stuart Broad also back from paternity leave, but with his allround credentials, Overton was unquestionably a player in England's thoughts for the coming summer.
In addition to his 97 at Headingley, Overton played a key role in Surrey's triumph in the County Championship, claiming 34 wickets at 25.64 in ten matches, including a best of 6 for 61 against Yorkshire at Scarborough. His absence will be a blow for Surrey's title defence, with received another setback on Wednesday with the announcement of Hashim Amla's retirement.
Along with his twin brother, Craig, Overton is one of six players on an ECB Pace Bowling Development contract, which tops up the player's county salary, by approximately £25,000, and gives the England management a say in managing their workload.