ShareRio Ferdinand handed former Manchester United team-mate Michael Carrick a warning after his full-time appointment as manager.Rio Ferdinand warned Michael Carrick he will have to keep getting results at Manchester United to maintain the respect of the players.Former United midfielder Carrick was initially appointed on an interim basis to replace the sacked Ruben Amorim in January.However, the Red Devils handed the ex-England international the role on a permanent basis after overseeing a turnaround in results and securing Champions League football with a third-place finish.Carrick has helped to restore a feel-good factor at Old Trafford after the struggles endured under Amorim, who was recently appointed as head coach of AC Milan.But Ferdinand, a six-time Premier League winner and a Champions League victor with United, warned his former team-mate that things could change quickly if he does not ride that momentum into next season."It's positive but listen, it's always positive when you're doing well," he told the Athletic of Carrick, who won five league titles and the Champions League with United as a player."I went in pre-season and interviewed Bryan Mbeumo, Matheus Cunha and Harry Maguire and I hadn't been around the club for a long time with the atmosphere really good. And then we started horribly. "So you need the results to help with the environment. And one thing I would say, speaking to Casemiro, he said, 'You can tell Michael Carrick knows the club, played football at the highest level, knows what’s in it'. "Roy Keane could walk into the Man United training room, command respect immediately."But if you don't get the result, that respect is gone quick, football players judge people very quickly. "Your history doesn't count for nothing, after a period of time. If you show that you're not the guy, or they're seeing chinks in your armour, it doesn't matter what you've done."You can have a career like me, Roy, Gary Neville, whoever, you'll be looked at down people’s noses."Rio Ferdinand handed former Manchester United team-mate Michael Carrick a warning after his full-time appointment as manager.Rio Ferdinand warned Michael Carrick he will have to keep getting results at Manchester United to maintain the respect of the players.Former United midfielder Carrick was initially appointed on an interim basis to replace the sacked Ruben Amorim in January.However, the Red Devils handed the ex-England international the role on a permanent basis after overseeing a turnaround in results and securing Champions League football with a third-place finish.Carrick has helped to restore a feel-good factor at Old Trafford after the struggles endured under Amorim, who was recently appointed as head coach of AC Milan.But Ferdinand, a six-time Premier League winner and a Champions League victor with United, warned his former team-mate that things could change quickly if he does not ride that momentum into next season."It's positive but listen, it's always positive when you're doing well," he told the Athletic of Carrick, who won five league titles and the Champions League with United as a player."I went in pre-season and interviewed Bryan Mbeumo, Matheus Cunha and Harry Maguire and I hadn't been around the club for a long time with the atmosphere really good. And then we started horribly. "So you need the results to help with the environment. And one thing I would say, speaking to Casemiro, he said, 'You can tell Michael Carrick knows the club, played football at the highest level, knows what’s in it'. "Roy Keane could walk into the Man United training room, command respect immediately."But if you don't get the result, that respect is gone quick, football players judge people very quickly. "Your history doesn't count for nothing, after a period of time. If you show that you're not the guy, or they're seeing chinks in your armour, it doesn't matter what you've done."You can have a career like me, Roy, Gary Neville, whoever, you'll be looked at down people’s noses."