The visitors, meanwhile, are experiencing a torrid run of form as they are hoping to end a six-game losing streak.
Match preview
Following a 10-day break from competitive action, Philadelphia came from behind twice to rescue a point in a 2-2 draw away against Orlando City on Thursday.
Second-half strikes from Jack McGlynn and Jose Martinez, the latter of whom netting a 90th-minute equaliser, helped the Union pick up their 11th away point of the campaign and maintain fourth spot in the Eastern Conference, although victory over Orlando would have seen them climb above New England Resolution into third place.
Hopes of Philadelphia retaining their Eastern Conference title appear to be slim as they find themselves 12 points behind league leaders Cincinnati just past the halfway stage; Indeed, five points dropped in the Union's last two matches has seen the gap increase this month.
While many will assume that Jim Curtin's side should have few problems returning to winning ways against a struggling Inter Miami outfit, Sunday's fixture may not be a cakewalk as they have won just one of their last five meetings with the Herons and have failed to win their last two encounters against them on home soil.
Philadelphia boast a strong home record so far this season, though, as they have accumulated 20 points from nine MLS games at Subaru Park, winning six times, drawing twice and losing just once - a 2-1 defeat to Orlando back in March.
Three days after edging past second-tier side Birmingham Legion by a 1-0 scoreline in the MLS Cup quarter-finals, Inter Miami suffered their sixth straight MLS defeat at the hands of New England Resolution, losing 3-1 away from home two weeks ago.
The Herons were three goals down inside the first 51 minutes before Josef Martinez netted a consolation strike from the penalty spot six minutes from time.
Inter Miami have now lost 12 of their 17 MLS matches this season, at least three more than any other team in either Conference division, and they remain rock bottom of the Eastern Conference standings, eight points behind the Final Series playoff spots.
Interim boss Javier Morales will be desperate to integrate new signing Lionel Messi into his side to provide a much-needed boost, but the club's owner Jorge Mas has confirmed that the seven-time Ballon d'Or winner is not expected to make his debut until July 21 when they face Cruz Azul in the Leagues Cup.
Inter Miami can ill-afford to drop too many more points in the meantime if they are to sneak into the top seven or nine of the Eastern Conference, and the Herons will hope that a fixture against Philadelphia - who they beat 2-0 on home soil in March - can spark a revival.
Philadelphia Union Major League Soccer form:
W
W
W
W
L
D
Inter Miami Major League Soccer form:
L
L
L
L
L
L
Inter Miami form (all competitions):
L
L
L
L
W
L
Team News
Philadelphia defender Damion Lowe missed the draw with Orlando due to injury and is unlikely to feature on Sunday, so Jakob Glesnes and Jack Elliott are set to continue at centre-back either side of full-backs Olivier Mbaizo and Kai Wagner.
Hungary's Daniel Gazdag and Kenya's Richard Odada are both in contention to return after representing their country during the international break, but Andre Blake is still away with Jamaica for the CONCACAF Gold Cup.
Top scorer Julian Carranza and striker partner Mikael Uhre have scored 15 MLS goals between them so far this season and the duo are expected to lead the line again on Sunday, with Gazdag potentially returning to start in the number 10 role just behind.
As for Inter Miami, Gregore (foot), Jean Mota (knee), Robbie Robinson (calf), Dixon Arroyo (groin) and Ryan Sailor (hamstring) are all ruled out through injury, while Franco Negri is doubtful after missing the last match due to concussion protocols.
However, Kamal Miller is available to return after serving a one-match ban and the centre-back will push Serhiy Kryvtsov and Christopher McVey for a place in the starting lineup.
After representing Venezuela during the international period last week, striker Josef Martinez is set to lead the line for Inter Miami and will be hoping to add to his four MLS goals this season; Corentin Jean and Nicolas Stefanelli are both expected to provide support for the 30-year-old on the flanks.
Philadelphia Union possible starting lineup:
Bendik; Mbaizo, Glesnes, Elliott, Wagner; Martinez; Flach, McGlynn; Gazdag; Uhre, Carranza
Inter Miami possible starting lineup:
Callender; Yedlin, Kryvstov, McVey, Negri; Ruiz, Fray; Jean, Cremaschi, Stefanelli; Martinez
We say: Philadelphia Union 2-0 Inter Miami
Inter Miami can draw optimism from their victory over Philadelphia earlier this season, but keeping the ball out of the net has been one of the main factors behind their downfall since then, and they may struggle to cope with a lethal Union attack, which has scored in 10 of the last 11 games, on Sunday.
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