The Red Devils have been strongly linked with a move for the 25-year-old Leicester City centre-back but have been quoted a world record fee for a defender for any deal to happen.
If Maguire joins Manchester United, the number of central defenders at Old Trafford will shoot up to seven with Eric Bailly, Chris Smalling, Phil Jones, Marcos Rojo, Victor Lindelof and Axel Tuanzebe all competing for a spot in the centre of defence.
When asked about his number of defenders, Solskjaer told reporters in Perth on Tuesday: "Of course, there's a limit of players.
"Whoever performs will be part of the team and whoever doesn't has a fight to get back in.
"There's been loads of speculation but I can't really say anything. We'll work to find a relationship with the ones we've got."
Reports of Spanish champions Barcelona eyeing a move for Lindelof have emerged this week but the former Benfica defender has insisted he is happy at Old Trafford.
Manchester United, who have signed two players in the shape of Daniel James and Aaron Wan-Bissaka, will continue their pre-season preparations with a game against Leeds United in Australia on Wednesday.
The Red Devils will begin their Premier League campaign against Chelsea at Old Trafford on August 11.
