Muttiah Muralitharan has been ruled out of the first Test against Pakistan in Galle starting on Saturday due to a minor knee injury. The offspinner hurt his patella tendon while training on the eve of the game and has been advised rest. The selectors have called up left-arm spinner Rangana Herath and offspinner Suraj Mohamed as replacements.

"He was doing his warm-ups and he suddenly felt a bit of discomfort in his right knee," Kumar Sangakkara, the Sri Lankan captain, said. "He bowled for 40 minutes after that and felt good. We took a precautionary scan, but he was feeling fine. The physio's advise was to wait for the report.

"We were very confident that he was going to make it. But the scan report showed a slight tear. So the risk of him tearing his tendon in the first Test is very high. I don't think we want to risk him getting injured for a long time just for the sake of one Test. We have got a lot of cricket coming. Hopefully he will be fit by the second Test (starting July 12)."

Mohamed, who is yet to play for Sri Lanka, took four wickets against the visitors in the three-day tour match in Colombo which ended on Wednesday. One among them will be expected to partner Ajantha Mendis, who is now the senior spinner.

Herath last played a Test in December during the tour of Bangladesh. He wasn't included for the tour of Pakistan earlier this year. Mohamed, 24, has played 50 first-class matches and taken 180 wickets. During the 2009-09 domestic season, he took 43 first-class wickets with two five-wicket hauls.