"S Sreesanth has sprained a ligament of his left knee, and been advised rest for 3-4 weeks. He will accordingly be returning to India," BCCI Secretary N Srinivasan said in a statement.
"The All-India Selection Committee has picked Munaf Patel as his replacement in the Indian team that will be playing the Test series in Sri Lanka. Munaf will join the squad at the earliest," he added.
Sreesanth was ruled out after an MRI scan revealed he has a ligament tear, a development which has come as a big blow for the India's already depleted pace attack in absence of spearhead Zaheer Khan who is nursing a shoulder injury.
With Sreesanth too being ruled out, Ishant Sharma would have to lead the pace attack, which also includes Zaheer's replacement Abhimanyu Mithun.
Meanwhile, it was probably the best birthday gift for Munaf, who turned 27 on Monday.
The lanky Mumbai pacer has played 12 Tests so far, his last being the match against New Zealand in Wellington last year.
India are scheduled to play a three-day warm-up match against Sri Lanka Board President's XI in Colombo, on Tuesday.