Adelaide - Australia captain Michael Clarke expects to miss his team's three remaining tests against India after injuring his hamstring on Saturday.
Clarke was sent for scans for the second time in the first test when he injured himself while fielding in the second session on the final day at Adelaide Oval.
He limped off with the assistance of the Australian team physiotherapist after reaching down to field a ball during India's second innings.
Clarke made it back to the field for the end of the match, which Australia won by 48 runs, and told Australian television the early prognosis was not good.
"I've just had a scan, results are not fantastic," Clarke said.
"The experts are looking at them now, but I think I'm obviously going to struggle to take any more part in this series."
Clarke, 33, has been troubled by hamstring and back issues since he was a teenager but the problem has flared up recently.
He almost missed the first test because of a recurring hamstring problem and suffered a painful back injury while batting in the first innings.
He retired hurt but recommenced his innings the next day, scoring a century.
Even if Clarke does make a quick recovery, the chances of him playing against India are remote with the four tests squeezed into a five-week window after the dates were reshuffled following the death of Australian batsman Phillip Hughes.
Australia is also co-hosting the 50-over World Cup early next year, starting in February, with Clarke looming as Australia's key player.
"I'm obviously disappointed. But I'll make sure I'm here supporting the boys and do whatever I can from the sidelines," Clarke said.