Sri Lanka offspinner Tharindu Kaushal has been banned from bowling the doosra in international cricket due to an illegal action. However his stock delivery, the offbreak, has been found to be legal in tests conducted by the ICC on his bowling action at the Sri Ramachandra University in Chennai.

The tests showed that while Kaushal's elbow extension was found to be "well within the 15-degree level of tolerance" for all his offbreaks, half of his doosras exceeded that limit.

Of the 18 doosras Kaushal delivered to a satisfactory standard during his test, nine were found to be within the 15-degree threshold. Elbow extension for his doosra was measured at as low as 12 degrees, with the highest measurements coming in at 21 degrees, for two separate balls. The average flexion for his doosra was 16 degrees. In the 18 offbreaks Kaushal delivered, his elbow did not exceed nine degrees of extension.

Kaushal was asked to provide 12 "good trials" for each delivery from over the wicket, and six "good trials" for each delivery from around the wicket. Of the six around-the-wicket doosras he bowled, four were found to be over the 15-degree limit. Five of the 12 over-the-wicket doosras were similarly illegal. Some trials were discarded on the basis of incorrect line and length, but the assessors had been satisfied Kaushal was replicating his match action throughout.

Both the bowler and his coaches had been confident Kaushal's offbreaks would be deemed legal after returning from the test, but did have concerns about the doosra. The doosra had also been the umpires' major concern when they reported Kaushal's action following the third Test against India. They had said in their match report that the flexion in his bowling arm appeared to be "more than the legal limit when he bowled the doosra, particularly when he got tired".

Kaushal and the Sri Lanka coaching staff have not decided whether he will undertake remedial work on his doosra. However, that remains a distinct possibility as even his worst delivery was only found to exceed the 15-degree threshold by six degrees. Sri Lanka Cricket has said that it is "committed to making every effort to assist Kaushal in taking corrective measures to permit him to bowl without restriction", should the bowler decide to bring the doosra within limits.

"The coaching department of SLC has confirmed that their staff will spend extra hours with Kaushal, studying his action, and the available video evidence, to achieve this end within the shortest possible time frame," the SLC release said.

If Kaushal does undertake remedial work on his doosra, he may submit to another independent biomechanical test in order to get the delivery cleared. He cannot bowl the delivery in internationals until he can prove its legality, however.

Sri Lanka had begun to groom Kaushal as the team's next spin spearhead. Though these test results are a setback, he is likely to remain in the frame for a Test-match place on the strength of his offbreaks. In six Tests so far, Kaushal has 24 wickets at 42.12.

The biomechanical test had been carried out on September 14 under the supervision of three biomechanists, a sports physician and an independent bowling coach. A motion-capture system and two high-speed cameras had been used.