Conor McGregor has been warned Michael Chandler could "send him into retirement" when the UFC icon makes his long awaited return to the octagon this year.McGregor 34, has been sidelined ever since his stoppage defeat to Dustin Poirier 18 months ago, which ended with 'The Notorious' being stretchered out with a broken tibia and fibula. Amid prolonged speculation over who he would face on his return, it was confirmed this month he and Chandler would go head-to-head as a culmination to their upcoming coaching roles on season 31 of The Ultimate Fighter.A date and venue has yet to be finalised, with McGregor yet to re-enter the United States Anti-Doping Agency testing pool.