Guy Whittingham has told John Akinde: Stay patient.
The powerful striker came on as a substitute in the 1-1 draw with Carlisle at the weekend and made a real impact, winning the penalty which Liam Walker converted.
After being handed a start in the 2-0 loss at Bournemouth the week before, the former Crawley man has since had to make do with a place on the bench.
But the caretaker Blues boss insists he has to protect the 23-year-old, who had not started a game all season before his Dean Court bow.
Whittingham said: ‘I think we’ve got to be careful with John. We want him for the rest of the season and we don’t want to lose him through injury so we are being careful how we introduce him.
‘John is here for the rest of the season as well and I pulled him in the other day and said “you just have to stay patient”.
‘He will get his fitness and what a great part he played in the goal as well.’
Akinde and fellow new recruit Patrick Agyemang have given Pompey a physical threat up front.
But with James Keene, David Connolly and Ashley Harris also in the mix, Whittingham now has a few more options to choose from.
He said: ‘We know we have two good assets there with John and Patrick.
‘We are pleased to have them and we want to keep them for the rest of the season and that’s why we want to make sure they are fit for the rest of the season.
‘But those two give us a bit of extra competition for places and a few different options up front now.
‘That makes a difference.’