Matt Clarke has extended his Pompey stay until the end of the season.
The Ipswich centre-back has impressed this term and was expected to sign a new loan deal, particularly after forcing his way back into the starting line-up in recent weeks.
The 19-year-old has made 21 first-team appearances and scored his first goal for the club in the 3-0 win over Crawley at the weekend.
But as part of the loan agreement, he is ineligible to play against his parent club in the FA Cup third round clash this Saturday.
Clarke said: ‘I’m delighted because I’m happy here and looking forward to seeing what the rest of the season brings.
‘I’ve come a long way from my earlier games and I’ll only get better playing alongside the guys at Pompey.’