Kusal Perera is almost certain to be out of Sri Lanka's series against India, after picking up a shoulder injury. The team has not divulged the exact nature of the injury, nor withdrawn him officially, but a team doctor says he's likely to be out for six weeks.

Although Perera is no longer captain, having been replaced in that role by Dasun Shanaka following the contracts standoff between the players and the board, he remains one of Sri Lanka's key batters in the top order. He is, in addition, the team's primary wicketkeeping option, with Niroshan Dickwella still suspended over his breach of the team bio-bubble, in Durham. Perera's probable absence, as well as that of Dickwella, Kusal Mendis and Danushka Gunathilaka (all of whom bat in the top five) means that Sri Lanka will only have what is essentially a second-string top order.

Although Perera has not been in particularly good form recently, he has been one of Sri Lanka's best batters. He was one of Sri Lanka's three half-centurions in the ODI series, against England, and struck his team's most-recent century, when he hit 120 off 122 balls to lead Sri Lanka to their only win in a three-match series against Bangladesh.

Sri Lanka have not officially named their squad yet. The first of three ODIs against India, who are fielding a second-string side, is scheduled for Sunday.

Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @afidelf