Kenny Jackett believes Pompey’s ‘stuttering’ displays have impacted upon Ronan Curtis’ form.
And he has backed the out-of-sorts Irishman to rediscover his spark.
Curtis’ starting spot is under threat against Bolton, with Marcus Harness back from injury and Ryan Williams’ Southampton showing indicating he is now ready to challenge.
Despite two goals in 10 appearances this season, the Republic of Ireland international has failed to recapture the high standards set last term.
There was further disappointment in Tuesday night’s Carabao Cup defeat to Southampton, when his mistake allowed the visitors to register a second goal through Danny Ings.
But Jackett reasons Curtis’ individual game has been affected by the Blues’ general shortcomings.
He said: ‘Ronan has to keep working hard for us, making sure he both comes inside and goes outside – and varies it.
‘There have been a lot of good left-footed deliveries from him, although people generally know he is coming inside to shoot, so he has to mix his game up and vary it.
‘In terms of goalscoring, he probably hasn’t got as many as he would have liked, and also the team have stuttered.
‘The way the team is playing has been slightly disjointed, I don’t think we have hit the heights yet. There have been games like Wycombe, where we just didn’t get it right, it didn’t work.
‘It was still a 50/50 game, but even so, when you are looking to individuals there is always a bigger picture of the team – and I do think that is the case with Ronan.
‘He has to keep working away. He was maybe frustrated with his pass for Southampton's second goal, a key goal just before half-time, but he then came out and had a really good second half.
‘That shows excellent character, he can never be faulted for effort.
‘In terms of assists and goals, they are big things, and he really must keep working away to try to get the levels we need and want from our forwards.’
With Lee Brown still sidelined through injury, Curtis has recently been asked to strike up a left-sided understanding with Brandon Haunstrup.
And while the Waterlooville youngster has impressed, Jackett still seeks for the fledgling partnership to gel.
He added: ‘The left-sided partnership is one of a number of components the team must go through to improve.
‘I’m looking at a left-sided understanding, ultimately left-sided productivity, stopping the opposition one way but, importantly, going the other way to create. We need to keep working and improving.’