Pompey have ended their interest in Lawrie Wilson.
The right-back spent the end of last week training with the Blues following his release by Bolton.
However, manager Kenny Jackett has decided against recruiting the 29-year-old and informed him of his decision on Friday.
Harry Isted, though, will continue to train with Pompey as they seek to bolster their goalkeeping ranks.
The 20-year-old from Selsey is a free agent following his release from Stoke at the end of last season.
In Saturday’s 3-0 friendly win at Salisbury, Alex Bass and second year scholar Jack Collins each featured for a half.
Brighton’s Christian Walton remains the club’s number one target on a loan spell.
Jackett said: ‘Lawrie was here, but we haven’t pursued that one.
‘I think Harry will be around because obviously we are short in that area at present.
‘He may be around to help us out and if he shows promise then we will capitalise on it.
‘Christian Walton is Brighton’s goalkeeper and I don’t like talking about other teams’ players.
‘Are we looking for a goalkeeper? Yes we are.
‘But individuals are other teams’ players and I don’t necessarily like to comment because I am not keen when other managers talk about my players.’
A number of Championship and League One clubs are also in the hunt for Walton, whose priority lies in regular first-team football.
The 21-year-old spent the first half of last season on loan at Luton and Brighton have high hopes over his ongoing development.
Fratton Park would offer the opportunity for more crucial experience.