India\'s field hockey authorities have lifted a two-year ban on top defender Sandeep Singh and midfielder Sardar Singh, an official said on Wednesday. The duo were suspended last month from international tournaments for indiscipline after they left a training camp without permission in the southern city of Bangalore. \"They have given an unconditional apology in writing. This is the final warning and any indiscipline in future will attract a reinforcement of the ban,\" said Hockey India executive director Anupam Ghulati. \"The committee decided to revoke the ban considering their age, performances at the top level and potential.\"The duo are now eligible for selection trials to pick the squad for a four-nation tournament in Australia next month, he added.Both the players missed the Asian Champions Trophy tournament, won by India in China early this month.