The Spanish champions are currently second in the table, four points behind leaders Real Madrid, who will win the title if they manage to beat Villarreal on the same night.
It is difficult to be too crucial of Barca, but there is no question that the Catalan giants have not been at their best since returning to action last month following the lockdown period.
Quique Setien's side have won each of their last three league games against Villarreal, Espanyol and Real Valladolid but drew three of their four between June 19 and June 30 to hand the advantage to Real Madrid.
As mentioned, Zinedine Zidane's team will win the title if they beat Villarreal on Thursday, while two draws in their final two games would also be enough due to their superior head-to-head record over Barca.
The reigning champions must win their last two against Osasuna and Alaves and hope that there is a slip from the leaders, but it is difficult to imagine that happening at this stage.
It could still be a successful campaign for the club, though, as they will face Napoli in the second leg of their last-16 Champions League clash on August 8 and are certainly capable of being a threat in that competition, even if they are to release their grip on the La Liga title.
Barca were held to a 2-2 draw by Osasuna earlier this season, but they recorded a 7-1 victory when the two teams last locked horns at Camp Nou in April 2017.
Osasuna were promoted back to this level courtesy of winning the Segunda Division last season and therefore consolidating at this level was always going to be their number one priority.
As it has turned out, though, Jagoba Arrasate's side have performed above expectations in Spain's top flight this term and currently sit 11th in the table, 16 points clear of the relegation zone.
They are only three points off eight-placed Athletic Bilbao, meanwhile, and will fancy their chances of finishing their season with a positive result at home to Mallorca this weekend.
Los Rojillos have not actually beaten Barca at Camp Nou since May 2009, but they will enter this match in impressive form, winning four of their last six in the league, including a 2-0 win over Celta Vigo on July 11.
Osasuna's away record this season has also been impressive, losing just seven of their 18 matches, picking up 21 points in the process, which is extremely strong for a newly-promoted side.
Barcelona La Liga form: WDDWWW
Osasuna La Liga form: WWWDLW
Barca will again be without the services of Ousmane Dembele due to a long-term hamstring injury, while Antoine Griezmann is also a major doubt, having been forced off at the interval of the clash with Valladolid.
Griezmann complained of a thigh problem during the first half of his side's 1-0 win, and it seems unlikely that the France international will be available for Thursday's clash.
Barcelona possible starting lineup:
Ter Stegen; Semedo, Pique, Lenglet, Alba; Roberto, Busquets, De Jong; Vidal; Suarez, Messi
Osasuna possible starting lineup:
Herrera; Garcia, Navas, Hernandez; Vidal, Moncayola, Merida, Lato; Arnaiz, Gallego, Barja
We say: Barcelona 2-0 Osasuna
Osasuna are certainly capable of making it a very uncomfortable evening for Barca, but we are finding it difficult to look past the champions, who have to win and hope that Real Madrid slip up. We cannot see anything other than a routine home victory for Setien's side.