Colombo: Sri Lanka Cricket (SLC) has issued a show cause notice to Lasith Malinga after the pacer defied Board's dictate by joining Mumbai Indians in the ongoing IPL without required medical clearance.

Sources in the SLC has confirmed that Malinga has been asked to explain his conduct.

Despite the Board not giving him permission to play in the Indian Premier League, the speedster has reportedly joined the Mumbai Indians squad on Friday and also took part in team's training session.

Malinga and the new SLC hierarchy have been at a standoff since the Asia Cup T20 in February.

The Board administration had asked Malinga to step down as the captain of the team before the World T20 last month in obvious annoyance.

Although Malinga made it to Sri Lanka World T20 squad as a player, he once again opted out of the crucial tournament, citing fitness issues.

As a result, Sri Lanka were forced to play the tournament without their main bowler, which turned out to be one of the main reasons for the defending champions ouster from the World T20 in the first round itself.

The SLC selection committee chairman Aravinda de Silva had said that he doubted Malinga's fitness claims and also insisted that his fitness would be proved when he would take part in the ninth edition of the IPL.

That had prompted Malinga to fire several media broadsides at the hierarchy, SLC sources claimed.