The News understands the two key men pinpointed for the role have now rejected the opportunity to move to Fratton Park.
That’s after Cambridge United’s Ben Strang followed Forest Green’s Richard Hughes in turning down the opportunity to assume the key position.
It means Pompey now have to go back to the drawing board after highlighting their two key candidates, following a two months of interviewing and undertaking due diligence on those in the frame.
Cullen has an extensive network of contacts throughout football he will once again call upon to identify the next in line for the position.
Another man who was being considered was Oxford United’s Mark Thomas.
A move for the U’s head of recruitment and performance analysis never accelerated, however, with Thomas happy in his role at the Kassam Stadium.
He is a man familiar with Pompey after spending four years at the club as an analyst, before going up the A34 to join Michael Appleton in 2014.
Thomas’ standing in the game has grown in his near eight years at Oxford, where the club have a long record of bringing in players and then moving them on in multi-million pound deals.
Kemar Roofe, Marvin Johnson, Rob Dickie, Gavin Whyte and Rob Atkinson are just some of those who fall into that category.
Thomas now potentially has the opportunity to work with an increased kitty next season when it comes to identifying talent, with Indonesian investors looking to up their stake in his club.
Former Pompey boss Andy Awford is another figure who’s been touted for the head of football operations position, after departing from his position as Luton academy and development manager last month.
The wait to bring in the figure for the position will be a source of frustration to those at Pompey, with Cowley calling for reform in the structure of the football operation at the club.
The reality is it will have little impact on the this summer’s efforts to strengthen the squad, with the existing football and recruitment staff taking that process forward.
But it’s now three months since Roberto Gagliardi’s departure was confirmed, as he took up a role with Southampton’s owners Sports Republic.
The position is seen as important in overseeing strategy and development when it comes to recruitment, performance, sports science, coaching, analysis and the club’s academy.