Mauricio Pochettino has suggested that Moussa Sissoko, Tottenham's £30 million summer signing from Newcastle United, has not shown enough in training or matches to be involved in the first team.
Sissoko has been absent from the match-day squad for Spurs' last two Premier League games -- the 3-2 win over West Ham and Saturday's defeat at Chelsea -- after returning from a three-match ban for appearing to elbow Bournemouth's Harry Arter. He has only started four Premier League matches for Spurs.
In January, Pochettino said that anyone costing £25-30 million would have to be the club's "best player" and he says he expected more from the deadline day signing.
"Football is not about money," Pochettino said after the 2-1 defeat at Stamford Bridge, when asked about Sissoko's absence. "It is about players being better, and that they show on the training ground that they are better than another teammate and that they deserve to be involved or not.
"In my opinion, I need to take the decisions and I believe that the players that started in the game [on Saturday] and the players on the bench deserved to be involved in the game. There's nothing else to it.
"It's not frustrating for me. It's about football. We can see in football different things that happen. You sign a player and then you expect something, and you don't find what you expected."
Pochettino included forwards Georges-Kevin Nkoudou, 21, Joshua Onomah, 19, and Vincent Janssen, 22, on the bench ahead of Sissoko on Saturday and the Spurs manager added: "If another deserved to be involved, like maybe Nkoudou or Josh Onomah, or Janssen, then why not?
"Just because we pay money [for someone], do they deserve to play? Sissoko needs to work hard and to show in future that he deserves to be on the team."