The Welsh club must overturn a 15-point deficit from their 34-19 defeat at High Wycombe to reach their second European final in a row.
But coach Lynn Howells has been forced to juggle his options at the back of the scrum with three back-row players and three scrum-halves out injured.
Michael Owen is the most serious concern after damaging medial knee ligaments during Pontypridd's surprise league defeat at Swansea last weekend.
His place is taken by veteran Dale McIntosh with Geraint Lewis still suffering from a shoulder problem and Nick Kelly out with a thumb injury.
Meanwhile Gareth Baber continues to wear the number nine jersey with scrum-half Paul John is still a week away from returning from his knee injury. Kevin Ellis, drafted in following John's injury, is also doubtful with a similar injury and replacement Jonathan Hooper picked up a shoulder injury last week.
'It is pretty hard to take when you have four scrum-halves registered and you lose three to injuries,' said coach Lynn Howells.
'You always want to have your best team available for a game of this magnitude and we could do without these problems. But we will just have to get on with it.'
The only other change to the side that lost the first-leg sees youngster Matthew Nuthall take over from Emyr Lewis following his impressive performances for the Grand Slam winning Wales Under-21 team.
Pontypridd: B Davey; G Wyatt, S Parker, J Bryant, M Nuthall; C Sweeney, G Baber; G Jenkins, M Davies (capt) D Bell, B Cockbain, R Sidoli, R Parks, D McIntosh, W O'Connor. Replacements: M Rees, N Hennessy, K Jones, M Lewis, N Jenkins, S James, K Ellis/J Lewis.