LONDON -- Baba Rahman must become more ruthless on the pitch to keep his place in the Chelsea team, according to interim manager Guus Hiddink.

A £21 million signing from Augsburg in August, Rahman has failed to establish himself in Chelsea's starting XI despite recent injuries to captain John Terry and Gary Cahill, with Hiddink picking winger Kenedy out of position over the Ghana international on several occasions.

Hiddink substituted Rahman at half-time of Chelsea's 2-1 win over Southampton in February after an error-strewn 45 minutes, and the Dutchman insists the 21-year-old must make it harder for incoming first-team head coach Antonio Conte to leave him out of the team next season.

"When you come in you have your impressions of players, and from Baba I had the impression after a few days that he was too quiet but very skillful in both legs," Hiddink said. "He has his left foot from nature but he can handle very well his right foot, which is unusual for left-footed players.

Baba Rahman, while skillful, needs to be more dominant defensively, says Guus Hiddink. Catherine Ivill - AMA/Getty Images

"This week I played him in some [training] games in the right-back position, because I was curious to see if he could do it. He did it without any problems. He's a skillful player but to survive also in the Premier League, he must make it difficult for a manager to take him out of the team.

"He has the skill but he must also be able to be dominant defensively. He's working on that. He's a very nice person and I said to him: 'Be a nice person outside the pitch but be less nice on it.'

"With experience I hope he can make the next step, because he has the skill. He has to get the attitude of: 'This is my area and whoever comes in, I kill them.'"

Rahman has made 18 appearances in all competitions for Chelsea this season and is in contention to start against Manchester City on Saturday, with Kenedy carrying a knock picked up in training at Cobham this week.