And the Pompey boss has outlined how he believes clubs like his will now start to wield the power in negotiations with free agents.
A deal has been tabled for the forward to stay at Fratton Park next season, after making a big impact following his January arrival from Sunderland.
The Republic of Ireland international established himself as a firm fans’ favourite across 17 appearances, with a clamour for him to stay continuing across the summer.
And the Londoner stated the contract tabled can only remain in play for as long as Pompey are still looking at attacking options.
Once moves for alternative options accelerate, that will signal the Blues moving away from pursuing the Londoner.
He said: ‘We’ve made Aiden an offer and that’s where we’re at with it. No (there hasn’t been any further conversations with O’Brien he’s aware of).
‘I think we made an offer and are actively looking to improve the squad.
‘So the offer can only stay there while we’re still looking to improve the squad.’
Most of the League One business done in the summer window to date has consisted of players joining sides after becoming free agents.
Pompey are certainly in the market to do just that, with the likes of O’Brien and Buckland boy Marlon Pack being pursued.
He explained how he feels the balance of power starts to shift from player to club, as teams begin to gear up for the new season.
That can lead to players who are biding their team over making decisions regarding their futures being more pro-active in securing deals.
Cowley thinks clubs returning for pre-season training can also be the catalyst for players on free transfers to realign, both the level they are looking to operate at and their financial demands.
He added: ‘Normally when players start to come back for pre-season, the players who are out of contract normally start to be a little bit more realistic.
‘I’m not talking about Aiden here, I’m just talking in general terms.
‘May and early June are very much the players’ market.
‘But once we start to get to the end of June and players start to come back for pre-season, the clubs start to have a bit more power.
‘That’s where it is at.’