Vaas, a another left-arm fast bowler is to undergo an operation on his ankle after hurting it during the First Test against South Africa which ended yesterday at Cape Town.
Zoysa played only two tests in New Zealand at the start of the 1997 season before breaking down with a thigh injury. He has not played any competitive cricket since then, but had been following a carefully drawn up physical build-up course by Sri Lanka's Australian born physio Alex Kountouri.
Zoysa was put to the test at the nets on Sunday under the watchful eyes of the national selectors and underwent a further trail on his fitness yesterday. He was also sent before the Sports Ministry's medical board for clearance.
Vaas, we understand is to be operated on by the doctor who treated South African fast bowler Allan Donald for a similar injury sometime ago. He is expected to remain in South Africa for treatment.
With the fourth seamer in the side, Sajeewa de Silva bowling poorly, Zoysa is expected to join Ravindra Pushpakumara and Pramodya Wickremasinghe to form the Second Test against South Africa starting at Centurion Park on Friday.