Alba and Busquets are both leaving Camp Nou on free transfers later this month, and the pair said their goodbyes in last weekend's home success over Mallorca, so they have not been named in the travelling party for the contest in Vigo.
Alejandro Balde is also absent for Barcelona, with the Spain international picking up an ankle injury during the last game against Mallorca, and he is now working to be fit for the start of pre-season.
Meanwhile, Ronald Araujo and Pedri remain on the sidelines due to muscular issues, with Xavi not taking any chances when it comes to the long-term fitness of the duo.
The absences have allowed Xavi to call up some youth players for the contest, with Marc Guiu, Pau Prim, Dani Rodriguez and Unai Hernandez all in the squad.
"The goal tomorrow is to win and give a good image. And others like keeping a clean sheet, winning [Robert] Lewandowski's Pichichi award... Celta are in a difficult situation, but we want to win," Xavi told reporters during his pre-match press conference on Saturday.
Lewandowski is currently top of the scoring ranks in La Liga on 23, five ahead of Karim Benzema, who will be involved in Real Madrid's final game of the season against Athletic Bilbao.
Barcelona secured the La Liga title in the middle of May, but Sunday's contest is huge for Celta, who sit 17th in the table, just one point ahead of 18th-placed Real Valladolid.
Xavi also again reiterated a desire to re-sign Lionel Messi this summer, with the Argentina international set to leave Paris Saint-Germain on a free transfer later this month.
"The priorities are very clear. I would really like Messi to return, I have spoken with him, and I have already said that it depends on him. From here, apart from Leo, the other priority is a pivot. That would be the ideal scenario," added the manager at his pre-match press conference.
"I'm not responsible for the financial issue. I only know that Messi would help us a lot in terms of football."
Barcelona have won 28, drawn four and lost five of their 37 league matches this season to collect 88 points, which has left them 11 points clear of second-placed Real Madrid.
Barcelona squad vs. Celta Vigo:
Ter Stegen, Pena, Tenas; Christensen, Kounde, E Garcia, Alonso; Kessie, Roberto, Gavi, Prim, Torre, U Hernandez, F de Jong; Dembele, Lewandowski, Fati, F Torres, Raphinha, Guiu, R Rodriguez