Centre-back Delpierre and star striker Berisha were forced off with hamstring and groin problems respectively in Victory's 4-2 extra-time loss away to Perth Glory in the FFA Cup quarter-finals on Wednesday.
Archie Thompson was withdrawn from selection contention before the game due to illness and while the veteran has been cleared to play at AAMI Park, defenders Adrian Leijer and Daniel Georgievski are suspended after being sent off at nib Stadium.
A lengthy absentee list will prompt some tinkering from Muscat, with Mark Milligan and Leigh Broxham likely to line up in central defence. Dylan Murnane is expected to play at left-back, with Archie Thompson moving into the middle of the attack and Fahid Ben Khalfallah starting on the left.
"Archie's fine," Muscat told reporters when asked for an update on Sunday.
"Matthieu (Delpierre) and Bes (Besart Berisha) have both got strains. We'll look after them. They need some more time to recover. It's not a real bad strain, fingers crossed they'll be available for next week's game.
"We've certainly got enough players and we've got enough quality to cover for the boys that aren't available. They'll be one or two not playing in their favoured position.
"Broxie (Broxham) and Millsy (Milligan) can play as central defenders, we've got two natural fullbacks in the players who are available, we've got two natural midfielders in there, we're comfortable. We'll have a strong side out."
Muscat admitted he was disappointed with the manner of Leijer's dismissal, the former captain picking up a second yellow card for dissent late on in Western Australia.
"A conversation has been had and will remain private. There's no-one more frustrated than the player himself," he said.
Muscat has been impressed by what he has seen from Wellington under former Big V coach Ernie Merrick so far in 2014-15, particularly the Phoenix's pace on the counter.
"There's shown some signs of certain patterns, especially in transition. They've got a little bit of pace in behind and they've caused teams problems with that, especially in their most recent game," he said, referring to a 4-1 win at home to the Newcastle Jets.
As for that fact that Victory have never lost at home to Wellington in the A-League, Muscat won't use the defence of that record as a motivating factor for his players, but has no intention of surrendering their unbeaten status.
"It doesn't mean too much to us going into tomorrow night," he said.
"It'd be nice for that to continue, there's no doubt. And that's the plan."