Meanwhile, the hosts can edge closer to the top of the Western Conference table with consecutive Major League Soccer wins of their own.
Match preview
After being thrashed 4-1 by Houston Dynamo, Real Salt Lake bounced back with a 3-2 victory over Dallas at America First Field on Thursday.
The Claret and Cobalt took the lead when Brayan Vera scored from the spot and quickly doubled their advantage through Anderson Julio's first goal of the game - however, the lead was cut short in first-half stoppage time when Jesus Ferreira found the net for Dallas.
Just two minutes after the hour mark, Julio scored his second goal of the game to restore the two-goal lead, and RSL held on for the win despite a nervy ending after Dallas' Alan Velasco converted an 88th-minute penalty.
The victory saw Pablo Mastroeni's side climb to second place in the Western Conference of the MLS table, virtually securing an automatic place in the playoffs.
Having won just two of their last seven MLS games, Real Salt Lake will be eager to put together a good run and finish the season strongly in preparation for the post-season.
However, on Sunday, they will face a side they have not beaten in their last three meetings, losing the most recent two.
The Portland Timbers are currently eighth in the Western Conference with 43 points, occupying one of the two temporary playoff spots - however, they are only two points behind Houston Dynamos, who hold the final automatic playoff spot.
Phil Neville's side are heading into Sunday's game on a high after securing a 4-2 victory over conference leaders LA Galaxy at Providence Park on Thursday.
The Timbers scored the first two goals of the game through Jonathan Rodriguez and Evander, but they went into halftime with just a one-goal advantage after Gabriel Pec pulled one back for the Galaxy.
In the second half, Portland added another two goals, with Evander completing his brace and Felipe Mora also finding the net, either side of Joseph Paintsil's goal for LA Galaxy.
Neville's men will be aiming for consecutive league wins in the MLS for the first time since July, but their away form may pose a challenge as the Timbers have lost four of their last five away games across all competitions.
Real Salt Lake Major League Soccer form:
D
L
L
W
L
W
Real Salt Lake form (all competitions):
W
L
L
W
L
W
Portland Timbers Major League Soccer form:
W
L
D
W
L
W
Portland Timbers form (all competitions):
L
L
D
W
L
W
Team News
Real Salt Lake will be without the duo of Kevin Bonilla and Pablo Ruiz, who are both nursing knee injuries.
The home side could also be missing Nelson Palacio and Javain Brown due to knee and leg injuries, respectively.
Cristian Arango, the league's second-highest goalscorer this season, is expected to return after missing the last match.
Portland Timbers' defender Claudio Bravo remains a doubt for this clash due to a leg injury that has kept him out of the last two matches.
Evander, who has been involved in five goals in his last four games, is the one to watch for the visitors.
Real Salt Lake possible starting lineup:
Beavers; Katranis, Quinton, Glad, Brown; Ojeda, Eneli; Luna, Goncalves, Brook; Arango
Portland Timbers possible starting lineup:
Crepeau; Mosquera, Araujo, Zuparic, K Miller; Ayala, Chara; Moreno, Evander, Antony; Toye
We say: Real Salt Lake 2-1 Portland Timbers
Portland may have won the last two encounters against Real Salt Lake, but they were the hosts in both games - the visitors have failed to win in their last two trips to America First Field.