India's Sai Sudharsan has been ruled out of the upcoming two-Test series in Sri Lanka, with Sarfaraz Khan named as his replacement, the country's cricket board said on Sunday.The Board of Control for Cricket in India said left-handed batter Sudharsan had made "significant progress" in recovering from a toe problem, but that Khan would replace him.The opening Test will begin on August 15 in Galle. The second Test will be played between August 23-27 in Colombo.The series will be India's first in the current World Test Championship (WTC) since the 2-0 home defeat to South Africa in November.India are fifth in the WTC standings, which are led by Australia, with Sri Lanka sixth.