Reece Topley could miss England's entire white-ball summer after sustaining a side strain.
Topley, the left-arm seamer, suffered the injury while playing for Surrey's second XI against Essex on Wednesday. He later underwent a scan which suggested he will be sidelined for four to six weeks.
England play six matches - three T20Is and three ODIs - against Sri Lanka between June 23 and July 4. They then play six more matches against Pakistan from July 10 to July 20.
Surrey have already ruled him out of the Vitality Blast campaign and the two County Championship games against Hampshire and Somerset which take place in the first half of July.
The news is a cruel blow for Topley who had fought his way back into England's white-ball squads towards the end of 2020 after several years out of the game due to stress fractures of the back.
The injury is the second major setback for Surrey's T20 Blast season in as many days, following Thursday's news that Sean Abbott would return to Australia after he suffered a hamstring injury in their Championship win against Gloucestershire.
They will be boosted by the returns of Sam and Tom Curran, and Jason Roy, for the first few rounds of fixtures. All three were due to play in an intra-squad match at The Oval on Friday night, which was washed out.