AITOR KARANKA will not be rushing to make further central midfield reinforcements despite facing the prospect of being without both Marten de Roon and Grant Leadbitter for the next month.

De Roon was substituted after just 22 minutes of his Middlesbrough debut in Saturday’s 1-1 draw with Stoke City, having damaged his hamstrings as he stretched to win possession.

The Dutchman faces up to a month on the sidelines, and is set to miss the forthcoming league matches with Sunderland, West Brom and Crystal Palace as well as the EFL Cup second-round game at Fulham.

The effect of his injury is compounded by the continued absence of Leadbitter, who is still around four weeks away from full fitness following hernia surgery earlier this summer.

Adam Forshaw partnered Adam Clayton for the final 68 minutes of Saturday’s game, and the former Brentford and Wigan midfielder is expected to feature in the starting line-up for Sunday’s trip to Sunderland.

The only alternative is inexperienced Belgian youngster Julien de Sart, but having shelled out £12m to sign de Roon from Atalanta, Karanka will not be returning to the transfer market in order to plug a short-term gap.

“I think it’s a muscle injury,” confirmed the Boro head coach, when asked about de Roon. “Sometimes that’s two weeks, sometimes it’s three – he wanted to show everybody he was ready to play.”

Having added full-back Fabio Da Silva to his squad on Friday, Karanka is close to completing his summer transfer business, although he would ideally like to recruit another defender before the transfer window closes at the end of the month.

He has discussed the possibility of a loan deal for Everton’s Brendan Galloway, who is also interesting Newcastle United, but the Merseyside club are reluctant to loan the youngster to one of their top-flight rivals.

One piece of contractual business was completed over the weekend, with George Friend penning a new four-year deal that commits him to the Riverside until 2020.

“We know how important he is to this club,” said Karanka. “It’s really good news that he’s signed the new contract. He’s a perfect son, perfect husband and he’s handsome – he has everything!”

Four of Boro’s summer signings were involved in Saturday’s season opener, with loan addition Alvaro Negredo claiming his first goal for the club as he bundled home an 11th-minute opener.

It was Negredo’s first Premier League goal since he scored for Manchester City at Newcastle in January 2014, and means he has now scored with his first attempt on target for each of his last two English employers.

“It’s important for strikers to score, and especially for Alvaro,” said Karanka. “When we signed him, I said that he needed to recover his confidence. But he’s won the Premier League with Manchester City so he can’t forget how to play.

“It’s been an amazing start, and now he’s got to keep working. He’s scored one, but has to keep working in the same way.”

Karanka was satisfied with his players’ efforts as they returned to the top-flight, with Boro having out-performed Stoke for long periods of the game.

The Spaniard felt his side were ready after a successful pre-season period, but admitted it was still a relief to see them more than hold their own against a Stoke side that are expected to challenge in the top half of the table.

“I can’t be disappointed with our attitude and performance,” he said. “You can’t forget that three months ago, Stoke finished in ninth position in the Premier League for the third season and we were in the Championship.

“I’m more than pleased. We had six or seven players who were playing their first game in the Premier League, so it’s been really good for me to know we are ready.

“This club is back where we belong, and this is just the first step. We were good for the first 45 minutes, but in the second half the game was broken and I don’t like to play in that way. It is a learning curve for me and the team, but we are here because we deserve to be here.”