Carrick threw Rashford into the starting line up for United's 5-2 Premier League win over Ipswich Town and he impressed on the left side of United's attack.
Rashford is now on course to stay at United for the 2026/27 season, after Barcelona opted against making his loan move permanent and Tottenham failed to launch an official transfer bid.
His return has received a mixed reaction from fans - but Carrick and Maguire are both feeling confident over the Red Devils 'new' No.9.
"He's added to the group for us, for sure, because it's pretty obvious," Carrick told his post-match press conference.
"I think he's making the most of that for us and for him as well, to have the opportunity to be here. He's one of our own. He's living his dream, playing here now, and trying to be successful and win.
"He's a great talent and always a threat," Maguire added.
"If Marcus wants to be here, wants to work, improve and help the team, of course we're willing to have him.
"He could still do a lot more and I think he'll say he can do more but if we keep him fit, we keep him happy, he keeps driven and hungry, he's a great asset to have."