Mata has struggled to convince the Chelsea boss that he deserves a place in his starting line-up. [Reuters]

Santi Cazorla has expressed his surprise over Juan Mata's struggles for first team football at Chelsea and suggests his fellow Spaniard may leave the club during the January transfer window in a bid to secure a place at next summer's World Cup.

Mata won the Player of the Year award in his two first seasons at Chelsea but this campaign he has started just 11 Premier League games under Jose Mourinho and he has been an unused substitute in the club's last three games.

Asking about Mata's exile from Chelsea line-up, Cazorla, who has a close relationship with his compatriot, said: "If he does not play he will want to leave Chelsea, this is obvious because it is a World Cup year."

Mata has been left on the bench in crucial games against Manchester United (twice) City, Arsenal and Liverpool during the season and with the summer's World Cup on the horizon his future appears increasingly likely to remain away from Stamford Bridge with Mourinho opting for Eden Hazard, Oscar, and Willian ahead of the Spain international.

"It's weird because Juan Mata does not play [but] he has proved his worth to Chelsea and to see him on the bench is weird. He should ask Mourinho to know why he does not trust him," Cazorla added in an interview with beIN Sport, after scoring a brace against Fulham in Arsenal's latest win.

Mata has recently been linked with a move to a number of teams and when asked of Paris Saint Germain's interest in the midfielder's services, the Arsenal star said: "For me this is a player who has proven his quality at Chelsea and if PSG gets him, they would get a very good player and would be a better team."

Cazorla has praised Arsene Wenger many times following his arrival in north London but when asked who has been his best manager during his career he pointed to Manchester City boss Manuel Pellegrini, who coached him at Villarreal and Malaga.

"Pellegrini is the best coach I have had, he brought me a lot. Wenger is a coach who is very close to the players, he is a very simple man," Cazorla said.