MANCHESTER -- Jose Mourinho has told Luke Shaw he still has work to do before winning a regular place in the Manchester United team.

Shaw made his first senior appearance since April when he logged 45 minutes against Burton Albion in the Carabao Cup on Wednesday.

But the 22-year-old is set to miss out on a return to former club Southampton on Saturday after Mourinho insisted he still wants more from the left-back.

"He has to work," Mourinho told a news conference on Friday. "Just that. You saw the game. You saw the same as I see. Are you asking if he plays [against Southampton]? No, he isn't. He has to work. He has to improve."

As well as coming off the bench during the 4-1 win over Burton, Shaw has also played three times for the Under-23s, including an appearance against Arsenal at centre-back.

Mourinho, who was critical of Shaw's attitude and application at times last season, says the defender is still getting back up to speed after damaging ankle ligaments in a 1-1 draw with Swansea on Apr. 30. But the United manager is prepared to be patient and cited managerial colleagues Antonio Conte and Arsene Wenger as being similarly cautious with returning players.

Luke Shaw has made just 48 appearances for Manchester United since joining the club in 2014. Martin Rickett/PA Wire

"Look, he doesn't play for six months," said Mourinho. "I'm not expecting him to arrive on Wednesday and be man of the match or to be running up and down for 45 minutes. It's a process. He doesn't play for a long time.

"You have other players in the Premier League who are not starting matches and their managers just say they're not in the best conditions. And we're speaking about some of the best players in the league. I heard last week the Chelsea manager saying that. The Arsenal manager said that.

"The players are not in their ideas, they're not in the best form after important injuries. Luke had surgery and a long time without playing. I cannot expect him to be back and strong, strong, strong in his work."

Mourinho was linked with a move for Tottenham left-back Danny Rose during the transfer window, although a move never materialised.

He has used three different right-backs and four different left-backs already this season but insists that, despite the competition for places, there will be opportunities for Shaw once he is fully fit.

"I played Champions League with Ashley Young at right-back, not [Antonio] Valencia. I played [Matteo] Darmian in the last match, not Valencia.

"At left back we've played [Daley] Blind, Young, Darmian, Shaw and, in a few weeks, [Marcos] Rojo too hopefully. It depends on the moment, what I see in training and the opponent."