AITOR KARANKA has already started to drill a message for next season in to his Middlesbrough players: 'Cut out indiscipline on the pitch'.

Boro – who it has emerged have until May 20 to turn Jozsef Varga’s loan in to a permanent arrangement - ended their home fixtures with a comfortable 3-1 win over relegated Barnsley at the Riverside on Saturday when another two players picked up yellow cards.

Ben Gibson's fifth caution of the season for handball and Nathaniel Chalobah's fourth took the team's tally to 79 bookings for the campaign – one of the worst in the Championship.

Throw in the nine sending-offs and the number of cards handed out to Middlesbrough's players over the last eight months does not make happy reading.

Midfielder Dean Whitehead could still miss the first three matches of next season, and be requested to go before a disciplinary hearing, if he was to pick up a 15th caution at Yeovil Town this weekend.

At times the suspensions have not helped Karanka's cause, considering the amount of times he has been forced to tinker with a winning team.

Improving his side's behaviour on the pitch is one of his priorities ahead of his first full season in charge.

“We need to improve that side of our game," said Karanka, who took over in November. "We have had too many red cards and yellows - that is a fact.

"We have to concentrate on the game, win the game and not get involved in other things. That's how we end up with more yellow cards, when players lose their focus.

"I have spoken to them already about it. They know I am not happy with the yellow cards we have picked up.

"I was never booked for saying something to the referee in 15 years of playing professionally - I have never seen a referee change his decision, so why argue with them and get booked."

It is hard to gauge the true extent of the effect suspensions have had on the team's performance over the course of the campaign.

But Karanka clearly feels he has had to tinker at times with his starting line up unnecessarily when injuries have already played a significant part.

The likes of Rhys Williams - who his club boss believes will not make the Australian World Cup with an Achilles problem - and Daniel Ayala have been sidelined for lengthy periods.

Skipper Jonathan Woodgate was also forced off again in the first half against Barnsley, which could mean he misses the final game at Yeovil on Saturday. George Friend's recurrence of a groin problem will also be monitored closely.

The injuries and suspensions this season have allowed young defender Gibson to be given his first team opportunity.

He has won over Karanka, who has even picked the 20-year-old ahead of more experienced campaigners like Woodgate at times because of his good form.

Having seen signs of inexperience in aspects of Gibson's play, however, Middlesbrough's Spanish boss is keen to keep the academy graduate's feet on the ground.

"Ben Gibson has impressed me a lot so far since I have been with the club," said Karanka. "He has shown he is a good defender and that he can grow as a player but he needs to improve a lot too.

"His character is good. His ability is good too which has impressed me. But he has made mistakes as well so he will get better with more games and experience.

"I am very happy with him because he has had eight good games for me recently but he has made mistakes too. He needs to improve still.”

Gibson was asked to slot in at left-back in the absence of Friend at the weekend. Woodgate's latest problem could mean he reverts to a more central role at Yeovil.

With Middlesbrough sitting nine points off a play-off place and 18 ahead of the relegation spots going in to the final weekend, Karanka could use the Yeovil date as a chance to see some youngsters in action.

He had been keen to respect the Championship at both ends of the table, suggesting he needed to field his strongest sides.

But with Yeovil already certain of a place in League One come August, the likes of Bryn Morris and David Atkinson could be give a run-out like Adam Reach did against Barnsley.

Varga, meanwhile, has been informed an agreement must be in place before May 20 if Middlesbrough are to take advantage of the first option they have to buy him. Debrecen, the versatile midfielder’s club, initially granted Tony Mowbray’s request to loan him.

Varga’s best performances, though, have arrived at right-back under Karanka, who can only have been impressed with the consistency the player has shown in that role.