Middlesbrough seem set to appoint an interim successor to Aitor Karanka before making a longer-term appointment in the summer, with the job apparently Steve Agnew’s to lose.

An amalgam of excessive tactical caution and questionable man-management prompted Karanka’s sacking on Thursday, leaving Agnew, his assistant, in charge for Sunday’s game at home to Manchester United.

Agnew, who is scheduled to address the media on Friday, is much admired by Steve Gibson, Boro’s owner, and will retain the post provided he impresses. But the hierarchy have sounded out alternatives, with Peter Kenyon, a club consultant, making an approach to Guus Hiddink.

Kenyon, a former Manchester United and Chelsea chief executive, knows the 70-year-old well but appears to have some serious persuading to do to get his man should results go awry for Agnew.

Gibson is not particularly close to Nigel Pearson, the former Boro captain and Leicester and Derby manager, but he did approach him about possibly taking over when Karanka was temporarily suspended last season and Pearson would be keen to attempt to keep his old club in the Premier League.

With Alan Pardew, Roy Hodgson, Steve McClaren and Claudio Ranieri also immediately available, Boro have options. For the moment at least, Karanka’s largely Spanish backroom team remain in post.

Karanka’s three years and four months on Teesside were characterised by a number of falling outs with players and staff members, with certain senior professionals going for weeks on end without having a significant conversation with the manager.

A watershed was reached when Stewart Downing – a former England winger who spent considerable periods of time in the club’s metaphorical deep freeze – had a bitter training-ground row with Karanka last week.

When the manager excluded Downing and Patrick Bamford from his squad for last Saturday’s FA Cup defeat at home to Manchester City, claiming that he wanted only “fighters” playing for him, red flags were raised and boardroom talks triggered. The conclusion was that locker-room trust had been eroded and change offered the best hope of avoiding relegation.

With Karanka having also become disillusioned with Álvaro Negredo, Boro’s main striker, the underperforming playmaker Gastón Ramírez proving to be a source of dressing-room tensions and Ben Gibson, the team’s key defender and nephew of the owner, publicly questioning overly defensive tactics, it is believed the club had begun making contingency plans for life after Karanka some weeks ago.

Although Gibson Sr had hoped he would remain in situ until the end of the season, a run of 10 league games without a win, featuring four draws, six defeats and only four goals scored as Boro dropped into the bottom three, hastened his departure. The Teessiders have won only four league games this season, scoring just 19 goals.

Karanka, a former Real Madrid defender who assisted José Mourinho there, was Boro’s first foreign manager and led them to automatic promotion last season.

Right until the end he retained staunch supporters, including Víctor Valdés, the former Barcelona and Manchester United goalkeeper who tweeted his thanks on Thursday, posting: “When football said ‘no’ to me, you were the only one who gave me the option to enjoy this beautiful sport again. I will always be grateful.” Other appreciative messages were tweeted by Negredo and the midfielder Marten De Roon.

Gibson enjoyed a strong relationship with Karanka, and the parting is believed to have been amicable and highly civilised. In a classy exit statement Karanka, who said his goodbyes at the training ground on Thursday morning, shaking a fan’s hand on the way out, said: “I’d like to thank Middlesbrough for a wonderful opportunity and the players, staff and all the people at the club. I’d also like to thank the fans for their support. This club will always hold a special place for me and I wish everyone connected with Middlesbrough football club the very best for the future.”

At times his zealous perfectionism and control-freak tendencies made a manager briefly suspended by the club following a training-ground tantrum this time last year overly demanding. Although he undeniably raised overall standards, certain players felt him a little overbearing in attempting to exert too much control over their off-field lives.

A workaholic who produced 80-page dossiers on opponents and believed defence was the best form of attack, Karanka did not like to be contradicted. His recent criticism of fans who chanted “attack, attack,” raised boardroom concerns but his substantial achievement in returning Boro to the top tier after a seven-year absence will not be forgotten.