Maguire's contract is due to run out at the end of the season whilst his teammate Mainoo is tied down until next summer with an option of a further 12 months included.
Since the arrival of Carrick, the pair has thrived in the first team after failing to impress under former manager Ruben Amorim who could not get the best out of the pair.
Mainoo failed to make a single Premier League start in 2025/26 until the Amorim was sacked by the board in January.
However, he has become integral under Carrick over the past few months and now journalist Ben Jacobs reports is set to be handed a new deal alongside Maguire.
“Kobbie Mainoo and Harry Maguire both set to sign new Manchester United deals, as @David_Ornstein called.
“Maguire finalising a 1+1 contract having indicated to the club last year he wished to stay. England defender keen to resolve future ahead of the World Cup. All parties have been confident since late January on a new contract.
“Mainoo’s new 2031 deal also advanced and expected to be completed soon with #MUFC aware of the need to improve terms to match his squad standing.”
United sit third in the Premier League with eight games remaining as they track down Champions League football which will only help the club finance deals for Mainoo and Maguire who could sign on the dotted line in the coming weeks.