Sri Lanka Cricket confirmed that paceman Lasith Malinga has a stress reaction in his knee and will require rest which means he is unlikely to play on the England tour in June.
The 32-year-old Malinga, who has had the injury since November last year, did not play in the recent World T20 and was ruled out of the ongoing Indian Premier League with the Mumbai Indians.
It was thought that he would need surgery but it looks like he will only go under the knife if the injury worsens.
SLC medical committee chairman Dr. Harindu Wijesinghe: "Malinga is suffering from a stress reaction in the knee.
"This has been caused by pressure being put on the knee. There is a chance that a stress reaction could worsen to a stress fracture, at which point he would need surgery."
Sri Lanka tour England in May with the limited-overs leg of the tour only taking place in June but Wijesinghe could not put a date on when Malinga will be fully fit.
Wijesinghe said: "A few doctors have been advising Malinga, and we feel that he needs to rest his knee, while undergoing physiotherapy and strengthening.
"Only after seeing how he the injury reacts to this, will we be able to say how long he might be unavailable. It might be a number of months before we decide to scan and test him again. It's difficult to put a time frame on his recovery."