Sri Lanka are preparing to bounce back after a heavy defeat in the first Test against India, but injuries to key batters have added to their concerns ahead of the series finale in Colombo.Experienced batters Kusal Mendis and Dinesh Chandimal are set to miss the second Test, while the fitness of another important batter, Pathum Nissanka, remains uncertain.Sri Lanka lost the Galle Test by 165 runs and now need a strong response in Colombo to level the two-match series.Mendis has been out of action since suffering a hamstring injury during the Lanka Premier League. He also missed the opening Test. In his absence, Niroshan Dickwella made a strong case for himself by scoring 80 in the first innings and could retain his place in the playing XI.Chandimal, meanwhile, is unlikely to recover in time for the second Test after suffering a shoulder and neck injury while fielding near the boundary on the fourth day in Galle. He was subsequently taken to hospital.Pasindu Sooriyabandara replaced Chandimal as a concussion substitute and could keep his place despite being dismissed for a duck on his Test debut.Under the ICC's concussion replacement regulations, a player suffering such an injury cannot return to the field within seven days, effectively ruling Chandimal out of the second Test.Nissanka's availability is also uncertain. The opener underwent wrist surgery in June and has yet to regain full fitness. Although he is closer to returning than Mendis, he is still experiencing discomfort while batting.Sri Lanka Cricket have yet to announce the final squad for the second Test. With the series on the line, the hosts now face a major selection challenge as they look to find the right combination against India.