Paul McCallum has pledged to repay Andy Awford for standing by him.
The 21-year-old striker has endured a troubled start to his Pompey career after being given a seven-match ban.
The West Ham loanee’s dismissal for violent conduct against Southend in January was punished further by a charge of improper conduct.
McCallum’s spell on the sidelines then coincided with a torn groin picked up in a Blues reserve friendly at Woking.
Now he is back in the first-team frame, having climbed off the bench in the last two matches.
The forward also netted a hat-trick in the reserves’ 3-1 victory over Leyton Orient on Tuesday.
It made me realise I cannot do something stupid like that because it could affect my careerPaul McCallum
And he is keen to make an impact for Blues boss Awford as he bids to make up for wasted time.
McCallum said: ‘It has been a frustrating time for me, but it’s great to now start getting some minutes under my belt to make sure I am fit when called upon for the first team.
‘I tore my groin against Woking during my time out which stopped me from training and I had to go back to West Ham to receive treatment.
‘That kept me out of the seven games I was suspended for.
‘So it was the chance to heal and reflect.
‘It made me realise I cannot do something stupid like that because it could affect my career.
‘My contract is up in the summer and it could have been a silly mistake which cost me.
‘It happened in the heat of the moment, we were losing 2-1 and I have been stopped running forward, it has upset me and I have reacted silly.
‘Then I couldn’t believe I had been sent off and reacted silly again.
‘I realised what I had done and apologised straight away. It was wrong of me.
‘But the gaffer has shown faith in me and hopefully I can repay him.
‘I have learnt from it and we will move on now.
‘The only thing I can do is score goals and make the gaffer realise he has a goalscorer at the club and start me.
‘I got 25 minutes against AFC Wimbledon and obviously I don’t want to be coming off the bench.
‘I want to start matches so have to keep grafting away in training and make sure I am ready to play.’
McCallum took his reserve-team tally to four goals in two league games during an impressive display against Orient.
It was a timely goal haul in front of the watching Awford.
And with eight first-team fixtures remaining, he is also eyeing a contribution in League Two.
He added: ‘I did a couple of sessions at West Ham when I was fit and then came back down to Pompey and started training a couple of weeks ago. Now I’m ready to play.
‘Hopefully Tuesday shows I will score if given the chance – and I am very confident in myself that in upcoming games I will.’