Lokuarachchi, 21, a bright prospect who broke into the Sri Lanka team after the 2003 World Cup, returns after serving a four-month disciplinary ban following his involvement in a late-night car accident.
Herath, a 25-year-old who played the last of his three Tests against Pakistan in 2000, returns to the fold after consistent performances in domestic cricket and for the Sri Lanka A team during recent tours to South Africa and India.
Sri Lanka's selectors picked six specialist spinners in the training squad, a clear sign that they will adopt a spin-focused
Pace bowler Dilhara Fernando has been ruled out of the series after suffering another back injury.
Training squad: Marvan Atapattu (captain), Sanath Jayasuriya, Romesh Kaluwitharana, Kumar Sangakkara, Mahela Jayawardene, Tillakaratne Dilshan, Upul Chandana, Chaminda Vaas, Muttiah Muralitharan, Kumar Dharmasena, Nuwan Kulasekara, Saman Jayantha, Avishka Gunawardana, Russel Arnold, Chamara Silva, Kaushal Lokuarachchi, Rangana Herath, Nuwan Zoysa, Dinusha Fernando, Chamila Gamage, Charitah Buddhika Fernando, Dinuka Hettiarachchi, Thilina Kandamby, Darshana Gamage, Ruchira Perera.