Frank de Boer
De Boer leaves Ajax after six years at the helm and could be replacing Martinez at EvertonGetty Images

Frank de Boer is favourite to replace under pressure Everton boss Roberto Martinez after the former Netherlands international left Ajax after six years managing in the Dutch capital. Ajax were unable to land what would have been their fifth Eredivisie title in six seasons after failing to win on the final day of the season, allowing rivals PSV Eindhoven to retain their crown in a dramatic climax to the campaign.

De Boer won four league titles in his first four terms with Ajax, which also included a return to the Champions League, but PSV's recent return to dominance has led to his untimely departure. The 45-year-old has a stellar reputation as a player following a four-year spell at Barcelona and after making over a century of appearances for the Dutch national team.

"I began to realise more that it was time for something else," he told the Ajax official website upon the announcement of his exit. "That is better for me and I think also for Ajax. What I will do, I do not know yet. A year without a club is also an option, I'll see what comes my way."

Though De Boer is contemplating a spell out of the game, his time in the managerial wilderness could be short-lived. The former Galatasaray and Rangers midfielder has been installed as the bookmakers favourite to take over from Martinez at Goodison Park with the Spaniard on the brink of the sack.

Defeat to Sunderland was Everton's sixth in their last 10 league games, a run which has included one win and seen the Merseysiders plummet down the division. A third loss in a row to West Bromwich Albion on the final day of the season could see Everton suffer the ignominy of recording their worst top flight position since the 2004-05 season when they finished 17th with just 39 points.

"We tried to get the focus after being in the FA Cup semi-final and sometimes it drops the intensity," Martinez told BBC Sport, after the 3-0 loss at the Stadium of Light. "The effort we put in deserved a lot more."It was not an easy game and Sunderland had a lot of momentum with their focus on the league. We have one more game to get the winning feeling and perform in a manner in which we can get the three points and end the season better."

Sky Sports understand the Everton board, which includes Alexander Ryazantsev – the representative for new majority shareholder Farhad Moshiri - and chairman Bill Kenwright, could even decide to part ways with Martinez before the visit of West Brom. Though De Boer is unlikely to be installed before the weekend, there would be few stumbling blocks in completing a deal now he is a free agent.

Representative Guido Albers told NOS prior to De Boer leaving Ajax: "He would love to join a club like Everton or Valencia. It's all about the right philosophy and how they play football. That is what Frank is looking for."