CALUM CHAMBERS has been told he is not a guaranteed starter after moving to Middlesbrough, even if head coach Aitor Karanka admits the Arsenal defender has arrived to gain more experience as a centre-back.

Arsene Wenger, the Gunners boss, gave Chambers permission to head to the Riverside Stadium on a season-long loan last month and he could make his first appearance for the club when they face Crystal Palace at the Riverside tomorrow.

The move is designed to give the 21-year-old more first-team football in his preferred role at the heart of the defence, although he faces a battle to edge ahead of Daniel Ayala and Ben Gibson.

Ayala and Gibson have formed a formidable partnership over the last two seasons under Karanka and there is also the added competition from Bernando Espinosa this season.

The Middlesbrough boss said: “I never give guarantees to a player who comes in. I never did and I can't guarantee a player that. Victor Valdes came here and I can’t guarantee he would play. Alvaro Negredo came here and the same. They are big names but have to fight on the pitch and show everyone they are better than their team-mates.”

But Karanka, who was close to signing Borussia Dortmund’s Nevan Subotic earlier in the summer, did concede he would not have any concerns about leaving a regular out if he felt it was going to improve the team.

He said: “We have to think of the future but the past is amazing. The numbers with Ayala and Gibson are amazing. But if something changes we need to have an alternative.

“With Bernardo and Calum we have two really good alternatives. Calum sees himself as a centre half. I have spoken to him and he understands that is his best position.”

Chambers, an England Under-21 international, is versatile and many felt he would end up slipping in at right-back for Boro, possibly ahead of Emilio Nsue and Antonio Barragan.

Karanka said: “I think when you are his age you need to play to keep learning. I spoke with him and he understood the best thing for his career was to come here, and to keep growing. For that reason I was really pleased.

“I knew Calum had a lot of offers. The following day Jack Wilshere went to Bournemouth and he had 20 plus offers and I know Calum had a few offers too. For sure he will be a really good player for us.

“He has a lot of good things. He is now in the Under-21 squad. He is getting experience. He played alongside Gibbo in the Under-21s squad, national team. He has everything. He has to keep going and keep improving.

“He can play in different positions but we brought him here as a central defender. Now we have three and one isn't 100 per cent. We wanted someone in that position.

“I know he can play as a midfielder, sometimes as a right back. If he has to play right back, no problem, but for me he is a main central defender.”

Boro will also have Adama Traore, signed from Aston Villa on deadline day for £5m, in the squad for the visit of the Eagles and his new head coach is expecting big things over the next few years.

The 20-year-old cost the Villans £6m from Barcelona just 12 months ago and he has effectively replaced Albert Adomah in the squad, after he headed in the opposite direction for £3m rising to £6m.

Karanka said: “When I am doing a deal I try to do the best deal. The future will show if I was right. If Admoah played 200 games and gets 50 goals and Traore doesn’t play I have made a mistake.

“Everyone understood for Albert is was a good move. Villa is in the Championship but you look at the trophy cabinet and there is a European Cup there so they are not really a Championship team. It is a big step for him to a really good historic team in the world. I will be happy if he is successful at Villa and if Traore is successful here.

“Adama is younger. I can bring a lot of things from him to increase his value. His value is now less than last season. With me, and his Spanish team-mates, he will increase his value of the club not just for the team.”

Boro welcome back George Friend, Marten de Roon and Victor Valdes after injury, although Fabio da Silva faces six weeks out. Karanka is satisfied that his summer business, though, means his squad is well shaped going into the Palace test and beyond.

Karanka said: “It shows the ambition of the club. It shows just how strong our squad is when we have players who could have gone to others places but they have chosen to join us.

“It means that the club is doing really well. The players are happy to be at this club and they feel that it is the right step for their careers. As a club we should be proud.”