Michael Appleton backed Kelvin Etuhu to grow from his testing Pompey baptism.
But the Blues boss admitted his new boy has to quickly find his feet with his frail squad pushed to its limit.
Etuhu was handed a tough debut against his former side Cardiff on Saturday, after agreeing a deal until the end of the season.
The 23-year-old was thrown into the centre of midfield for the 3-2 defeat against the high-fliers, with Appleton shorn of options.
He was withdrawn after 64 minutes of his first competitive game since May 2010 – an absence enforced by a prison sentence.
Appleton had little choice but to turn to Etuhu with just 13 fully-fit senior players to call on for the trip to the Cardiff City Stadium.
He admitted it wasn’t a flying start for the Nigeria-born talent.
But he is confident he will show better form in the coming weeks – as he will need to.
Appleton said: ‘It was a difficult game for Kelvin to come into.
‘You could see why Cardiff are third in the league and in a cup semi-final.
‘He found it a little difficult to get into the game.
‘I didn’t really have any choice but to throw him straight in, though.
‘But I think that he will get better for us – I have no doubt about that.
‘He gives us that little bit of versatility across midfield.
‘He hasn’t played for a long, long time.
‘He’s a body and that is something we need with regard to our situation bringing players in.
‘He will bring that little bit of strength and athleticism we need in the midfield area.
‘Hopefully we’ll see some strong performances from him.’
Appleton is already bracing himself for his squad to be cut further with the club hit with an unpaid £1.6m tax bill.
Ipswich are preparing another bid for Joel Ward and Jason Pearce, after already having two efforts rebuffed.
The second of those, understood to be in the region of £1.4m, was knocked back on Monday, with Leicester also keen.
Stephen Henderson has been linked with a move to Newcastle while League Two outfit Swindon are said to be keen on Benjani.
The prospect of a squad which is already the smallest in the Football League being hit still further is a scary one.
That puts more emphasis on Etuhu getting into his stride.
Appleton said: ‘How long will it take for Kelvin to settle? It’s going to have to be quicker than it would normally.
‘We’ll have a look where he is fitness wise but we need him to get up to speed pretty much straight away.’