David Moyes has warned his failing Manchester United players he has run out of patience and will move them out of the club if they continue to underachieve between now and the end of the season.

In his strongest warning yet that he is not going to tolerate any more underperforming Moyes said: "I am not going to accept it. I am disappointed we are not in a much stronger position. I am disappointed with how we have played. I, ultimately, take the rap for that. But what I will do is make it right. I am going to get better players in. Unfortunately I don't think there will be more in January. But it will change."

Moyes has agreed to loan Wilfried Zaha to Cardiff City after repeatedly clashing with the former Crystal Palace player. Fábio da Silva is also joining Cardiff, United's opponents on Tuesday night for Juan Mata's debut, and there will be an overhaul of the squad at the end of the season. Rio Ferdinand is among those who will probably be let go.

Moyes added: "I have given every player the opportunity to play and show what they can do. We have had a pretty good chance to have a look at it. The players have to perform. If they want to be here and making sure they have a jersey, they have to show it in the games. Undoubtedly this club wants to be at the top. We want to be challenging. At this moment in time we have failed to do that. We want to do something about it."

He also warned that the "rebuilding process" is still only in its early stages despite Mata's arrival from Chelsea.

"The message this sends, as I said in the summer, is that we're going for all the best players in the world. Juan is one of those players. He's a top Spanish player, a top Premier League player and I think if you asked any supporter, no matter what club they support, they would be an admirer.

"There will be more players like Juan in the future, no doubt about that. He plays for Spain, he's played in big games already for club and country. I do see him fitting in and, hopefully, it doesn't take him much time. But I also still think coming to Manchester United is a big change, for any player or any manager. It's a big thing and he can't solve everything.

"I've got a big job to do here and a couple of new signings isn't all that is needed. I think there's a bigger job to be done but you have to start somewhere. If you asked me what I needed most, I would have said a central midfielder. I could do with a left-back, too, but sometimes you don't always get the pieces of the jigsaw at the time. It's all part of a rebuilding process."

Wayne Rooney and Robin van Persie have resumed full training after their recent injury issues and that means United will potentially have a new-look attack on the night when Ole Gunnar Solskjaer returns to Old Trafford for the first time as a manager.

"Juan has come to play three positions – off the right, off the left and behind the striker," Moyes said. "He gives me a lot of flexibility. I have been without Wayne for about a month, Robin for two months, and I think if I'd had Juan in that period, I'd more than likely have had better results. Juan will play in different positions, and we could have done with him in the last month or two."

United are six points behind the top four and Champions League qualification but now have a run of games, against Cardiff, Stoke City and Fulham, that presents the opportunity to make up some lost ground before they take on the leaders, Arsenal, at the Emirates on 12 February.

"Yes, we've definitely got an opportunity," Moyes said. "But I've been saying that since October and it's not quite happened for us. I don't know [if we can reach the top four]. It sounds like the stock answer but I'm probably going to have to win all of our remaining games. The only way you can start that kind of run is by winning the next one, then see where you go from there. But I've got to think, now that I'm getting players back, if we can get them match-fit, we have a chance."

The alternative would make Moyes' job of attracting his top targets considerably harder in the summer. "It's imperative," he said.