Zaheer Khan is likely to miss the second Test against England at Trent Bridge.
India's fast bowler missed most of the first Test at Lord's after pulling up with a hamstring problem.
Khan was seen towards the end of the Test using a cycling machine, suggesting he would not be out for the whole series, as first feared.
Indian medical staff are hoping to have him fit in time for the third Test at Edgbaston, which starts on Wednesday, August 10.