The Swiss squad has operated a single Gibson-powered LMP1 throughout the 2019/20 WEC season for Bruno Senna, Gustavo Menezes and Norman Nato, taking two race victories at Shanghai last November and the Circuit of the Americas in February.
Earlier this year, Rebellion announced it would be withdrawing from sportscar racing at the end of the current campaign, which was originally supposed to conclude with the Le Mans 24 Hours but will now come to a close at Bahrain in November.
Rebellion CEO Calim Bouhadra said that while the team hopes to be present in Bahrain, it depends whether Senna, Menezes and Nato still have the chance of challenging the two points-leading Toyota crews after Le Mans next weekend.
With just Le Mans and the eight-hour Bahrain season finale to go, Senna, Menezes and Nato are 28 points behind the points-leading Toyota trio of Mike Conway, Jose Maria Lopez and Kamui Kobayashi, with 90 still potentially up for grabs.
With only 39 of those available at Bahrain, the Rebellion drivers couldn't afford to drop more than 10 points to the #7 Toyota crew at Le Mans to remain in theoretical contention.
On whether he felt his team's title chances remain realistic, Bouhadra said: "It all depends on Le Mans because the points are doubled. It’s all-or-nothing.
"If we win, we can imagine to compete for the championship, but if we don’t win, Toyota will have enough advantage to have the championship in the bag."
Rebellion said financial worries were also partly behind its decision to withdraw the second car it had planned to enter at Spa last month.
Louis Deletraz, Romain Dumas and Nathanael Berthon were slated to share the #3 entry, which had not appeared in the WEC since last year's Silverstone round, but the team decided to prioritise taking part in a Paul Ricard test over the traditional Le Mans warm-up race.
"Even though we promised we would be at Spa with two cars, we prefer to be secure [financially], and be sure we can run two cars [at Le Mans]," said Bouhadra.
"The [second] car at Spa, obviously it’s a question of budget, but it was [intended] to practice for the team, also for the mechanics to work on the car and create this team.
"With the [revised] calendar, there were some clashes, and we felt to try and compete [at Spa] was not the right strategy. We decided to put our effort and budget into a private test, which we did at Paul Ricard [in July], which we thought was better to practice and get the knowledge ready for Le Mans. For us, the priority is Le Mans.
"It’s a shame because I would have loved to see two cars at Spa, but it was more realistic to follow this strategy to be ready at Le Mans with two strong cars."