In-form pace bowler Kasun Rajitha is out of the second Test against Bangladesh because of a back injury, Sri Lanka Cricket said.

The second and final Test begins in Chittagong on Saturday with tourists Sri Lanka leading 1-0 after their 328-run win in the opening match in Sylhet.

Rajitha played a big part with eight wickets in two innings, including 5-56 in the second innings.

Asitha Fernando has joined the squad as a replacement.

"Kasun Rajitha will not be available for the second Test match as the player has suffered an injury to his left upper back area," Sri Lanka Cricket said.

Fernando claimed 10 wickets the last time he played a Test match in Bangladesh, in 2022.

He last played a Test against Afghanistan in February.

He was initially ruled out of the Bangladesh series with a hamstring injury but recovered sufficiently to be drafted back into the squad for the second Test.

Sri Lanka have never lost a Test series to Bangladesh.