Kenny Jackett has demanded greater impact from Pompey’s substitutes.
The Blues manager believes the players thrown on from the bench haven’t done enough for their side this season.
Jackett is looking for his changes to contribute more to results than they have over the first half of the campaign.
The stats back up the view of the Pompey boss not enough impact is being made.
Before Brett Pitman’s late goal against Chelsea under-21s last week, Conor Chaplin was the only player to have scored this season when being introduced from the bench.
Chaplin has scored on three occasions when doing so – against Wigan, AFC Wimbledon and Peterborough.
Jackett said: ‘You need to be strong on the bench as well.
‘There are so many games which are tight after 60 or 70 minutes.
‘Substitutes can hold on to a lead or make the difference when you are behind.
‘Having the right players on the bench is important.
‘At times in the season we haven’t had enough impact off the bench.
‘I don’t think the people who have come off the bench have let us down but you do need people who can change games.
‘Some substitutes have, at times, been underwhelming.’
Jackett noted how having Connor Ronan is his ranks gives him another creative player to call upon.
That means more forward-thinking potential to use from the bench.
The Pompey boss is still keeping his options open when making further attacking additions this month.
He said: ‘We trust Connor but if the squad is a player or two over it’s better than being a player or two under.’