Matthews has been ruled out, but Randiv has replaced him in the squad. So no Vaas.
Presumably they will have to play Perera or Randiv at #7, and the #8 will be decided on whether they want to play the extra seamer or spinner.
Given that Herath hasn't impressed me all that much, and I think the Sri Lankan lower order needs all the help it can get, I'd go with a 7-11 of Perera, Randiv/Kulasekara, Malinga, Murali, Mendis.