Aaron Jarvis will have a week to earn himself a Pompey deal.
The striker arrived on trial as the Blues returned for pre-season training on Thursday.
Jarvis was a surprise face among Kenny Jackett’s squad following his release from Luton, after their promotion to the Championship.
The 21-year-old made 10 appearances for the Hatters last season, before spending the second half of the season on loan with Scottish outfit Falkirk.
Jackett confirmed he will be running the rule over the front man next week.
He said: ‘Aaron Jarvis was at Luton last year and he got released.
‘Before that, he was at Basingstoke. He’s 21, a centre-forward and 6ft 2in.
‘We’re trialling him and he will be with us for all of next week as well.
‘So we’ll make sure we get some footballing sessions into him.
‘He’s a centre-forward on trial.
‘Maybe he’ll be the last one, maybe not.
‘We’ve got quite a good balance in terms of the squad.
‘We won’t be wanting to go too many more over the number we have now.’
Jarvis joined Pompey’s five new faces at their Roko training base, after the summer break.
Sean Raggett, Paul Downing, Ellis Harrison and James Bolton were linking up with their new team for the first time.
Jackett reported they were all in decent condition, although Bryn Morris was in the treatment room after picking up a groin problem this summer
Ryan Williams was given permission to miss training after signing on Wednesday night, Christian Burgess was ill and Ronan Curtis has been afforded some extra time off after international duty with Republic of Ireland this summer.
Jackett added: ‘Our running times were better than last year across the board.
‘But you have to keep improving physically.
‘There was no one necessarily outstandingly and or off their times.
‘The new lads have a good standard of fitness.
‘Jack Whatmough, looking at him, has really improved since last year as well.
‘His quad, calf and shape of the knee has really come on. He’s had a busy summer.’