Phelan returned to Manchester United on an interim basis to work alongside caretaker boss Ole Gunnar Solskjaer, just days after Jose Mourinho was sacked by the club.
Solskjaer, surprisingly, will take the reins at United until the end of the season with Phelan temporarily leaving his role at Central Coast Mariners.
In an interview with Manchester Evening News in the summer, Phelan highlighted the importance of Carrick helping new signings understand the importance of playing for United.
“To be honest, the best way for players to learn is not just playing or practising in training but being around people who lived through it and experienced what they are going through,” he said.
“I think Manchester United have done that with ambassadorial roles and they have now got someone coaching in that environment who can help calm things down.”
World Cup-winning midfielder Paul Pogba has come under some intense scrutiny this season, having constantly not seen eye-to-eye with Mourinho.
The Frenchman’s commitment to club has been questioned by fans and numerous pundits but Phelan believes Carrick can help him too.
“It will be vital not just for Paul Pogba but new players coming in,“ he added.
“What the club stands for, what it takes to be well-respected as a Manchester United player, how to conduct yourself.”
Pogba returned to the club in the summer of 2017, after being sold to Juventus as a youngster in 2012.
But the 25-year-old has struggled to put in consistent performances since his return to Manchester.
“Paul understands that as a junior coming in from the academy,” Phelan said.
“He needs to take that time to pull back, to realise that dream. It’s a great dream.”
Solskjaer and Phelan will take their first session at United on Thursday morning at Carrington training ground.
Their first game in charge will then be away to Solskjaer’s previous employers Cardiff City on Saturday afternoon.