All indications are that Carrick will remain in the dugout for Sunday's meeting with Bournemouth, but following the loss to Como on Wednesday night, he is dangerously close to being sacked.
Antonio Conte, Eddie Howe and Negalsmann have been linked with the role as the United board look over potential replacements in what could be yet another switch for the club.
Nagelsmann has already managed Hoffenheim, RB Leipzig, Bayern Munich and Germany. Although he has never stepped into the Premier League, much like Erik ten Hag and Ruben Amorim in the past, he is considered a major candidate for the job.
However, Oliver Kahn, the legendary Germany goalkeeper, has warned him not to make the move to the Red Devils after over a decade of instability.
"The Premier League and Manchester United have not been known for much continuity in the managerial position in recent years.
"He has to ask himself: What is my next step? Does it have to be the right one? Or do I immediately associate it with an enormous risk like Manchester United, where essentially every manager in recent years has failed sooner or later? You should look very carefully at where you're going.
"Bayern Munich and the national team were already big blows for him. You have to think carefully: Where do my strengths lie? Which club can I really help? I think Julian is someone who can develop a club and a team and take them further. Whether Manchester United are the right next step for that is something only he can know."
Nagelsmann's Germany side were dumped out of this year's World Cup by Paraguay in the round of 32 on penalties. Reports suggest Howe is the leading candidate over the German as both managers eagerly await to see how United perform against Bournemouth this weekend in what may be a make-or-break clash.