Erik ten Hag says Manchester United need players who will “fight for the badge” and the club.
New co-owner Sir Jim Ratcliffe is expected to be at Old Trafford when United take on Tottenham on Sunday.
England winger Jadon Sancho rejoined Borussia Dortmund on loan for the rest of the season this week after falling out with Ten Hag over his training performances.
“If you want to perform, you need hungry players,” he said.
“We need personalities and players who are very hungry to fight for the badge and this club.”
United have lost 14 games in all competitions so far this season and the club are considering their options in the January transfer window.
The Dutchman added: “We need personalities and players who are very hungry to fight for the badge and this club.
“It is not about discipline, it is about normal behaviour. It is about what you can expect from a top professional.”
The key question for Ratcliffe and Ineos head of sport Sir Dave Brailsford is whether to stick with the strategy of putting an emphasis on youth and development rather than buying established players.
It is how United ended up targeting 20-year-old Denmark striker Rasmus Hojlund in the summer rather than England captain Harry Kane.
“We signed talent and talent needs time,” said Ten Hag.
“You see the progress from [Alejandro] Garnacho and Kobbie Mainoo, also from Rasmus Hojlund.
“You need time but at the same moment, we don’t have time. You have to deal with some setbacks but that belongs to the process.
“Is it difficult for me? No, it is not difficult because I could expect it from the start of the season that the process could go negative, then, as a manager, you have to stay positive and get the process in the right direction.”
United goalkeeper Andre Onana has remained in Manchester and is expected to face Spurs before flying to the Ivory Coast to begin his Africa Cup of Nations duty with Cameroon.