Pompey look to have missed out on a move for Simon Gillett after the midfielder opted to train with Nottingham Forest.
Meanwhile, David Preece and Lloyd Sam have both been told they will not be offered deals.
In addition, Luke Rodgers has been given another week to impress after his time in Spain was hampered by a groin problem.
Michael Appleton had been desperate to sign Gillett, who agreed to attend the recent 10-day training tour to Spain and Gibraltar.
The 26-year-old was one of the 12 triallists who featured during the time away and the Blues boss was eager to keep him.
However, with the club still unable to sign players, Gillett has opted to instead begin training with Nottingham Forest.
His former Doncaster boss Shaun O’Driscoll is now in the City Ground hot-seat and stepped in to offer him a chance.
Definitely not returning to Pompey will be Preece and Sam, who failed to impress Appleton in Spain.
Sam, a free agent after leaving Leeds, started both friendlies and created Dan Thompson’s goal in the 5-1 defeat to Brighton.
The right winger, though, didn’t do enough for the Blues boss to follow up that initial interest once returning home.
As for veteran keeper Preece, he stepped in after a previous target had pulled out of the tour through a family bereavement.
He was in goal for seven of the nine goals Pompey conceded in their friendlies on the tour.
The door remains open, though, for 30-year-old Rodgers.
The ex-Notts County, Shrewsbury and New York Red Bulls striker picked up an injury in the Gibraltar friendly.
That restricted his participation for the remainder of the week – now he has been given another five days to convince.