The visitors, meanwhile, have the chance to claim a third consecutive victory in all competitions after recording wins in the EFL Trophy and FA Cup in their last two games.
Match preview
Wycombe are currently experiencing a poor run of form after winning only one of their last six games in all competitions.
The Chairboys looked to have turned a corner when they claimed a 2-0 away victory over Forest Green Rovers thanks to goals from David Wheeler and Gareth McCleary.
However, they followed that positive result with a narrow 1-0 defeat to Cheltenham Town, which leaves them in 12th place ahead of Sunday's contest.
After heading on their travels for their previous two games, Wycombe will now return to Adams Park where they are currently winless in four competitive games.
They have missed opportunities to claim three points in their previous two home league matches after giving up leads to draw against Morecambe and Port Vale, which will frustrate Wycombe boss Gareth Ainsworth.
Meanwhile, Portsmouth are currently unbeaten in nine games across all competitions, and they have managed to progress in two cup competitions in their last two matches.
After beating Ipswich Town 2-0 in the EFL Trophy, Pompey faced MK Dons in the second round of the FA Cup last weekend.
Portsmouth were behind for just three minutes after Reeco Hackett cancelled out Darragh Burns's early opener, before Colby Bishop scored from the spot on two occasions, and although Mo Eisa pulled a goal back for MK Dons, Danny Cowley's side held firm to claim a 3-2 victory.
They will now look forward to a third-round tie against Premier League side Tottenham Hotspur, but they will turn their attention back to league matters this weekend.
Pompey currently sit two points adrift of the playoff places with three games in hand over sixth-placed Peterborough United, and they will be aiming to end a run of four consecutive league draws when they face Wycombe on Sunday.
Wycombe Wanderers League One form:
W
L
D
D
W
L
Wycombe Wanderers form (all competitions):
L
D
D
L
W
L
Portsmouth League One form:
L
W
D
D
D
D
Portsmouth form (all competitions):
W
W
D
D
W
W
Team News
Curtis Thompson is closing in on a return from injury, but he is unlikely to feature against Portsmouth, while Joe Jacobson misses out through suspension.
After dropping to the bench for Wycombe's last two games, Lewis Wing could return to the starting lineup for Sunday's contest.
Sam Vokes is expected to retain his place up front, and the forward will be looking to add to the three goals that he has scored this season.
As for the visitors, they are expected to be without the services of Jayden Reid, Louis Thompson and Tom Lowery due to injury issues.
After featuring as a second-half substitute against MK Dons last weekend, Connor Ogilvie could be included in the starting XI.
Bishop has scored 13 goals in all competitions this season, and he will be aiming to continue his impressive form when he leads the line against Wycombe.
Wycombe Wanderers possible starting lineup:
Stryjek; Grimmer, Mawson, Tafazolli, Obita; Freeman, Scowen, McCleary, Wing, Mehmeti; Vokes
Portsmouth possible starting lineup:
Griffiths; Raggett, Morrison, Robertson; Swanson, Pack, Mingi, Ogilvie; Hackett; Curtis, Bishop
We say: Wycombe Wanderers 2-2 Portsmouth
Although Pompey have won two consecutive games, their last four league matches have ended all square, and we think that they will play out another draw against a Wycombe side, who have drawn their previous two home fixtures in League One.