Vinicius has been struggling with knee inflammation over the last couple of weeks, while Benzema missed out against Sevilla last weekend due to a nasty foot injury that he suffered against Rayo Vallecano.
The pair are back in the squad for Real Madrid's final La Liga game of the season, though, where Carlo Ancelotti's side will look to secure second position in the table ahead of Atletico Madrid.
There are also returns to the squad for Asensio and Mariano, who have been out with muscular issues, and the pair could be seen for the final time in a Real Madrid shirt on Sunday.
Los Blancos confirmed on Saturday that Asensio and Mariano are both leaving this summer, with their contracts due to expire at the end of the month.
An agreement has also been reached to terminate Eden Hazard's contract this summer, but the Belgian is also in the squad for the contest with Athletic and will hope to be given the chance to say goodbye to the fans.
Ancelotti also seemingly confirmed that Benzema would be staying at Bernabeu for the 2023-24 campaign despite strong reports lining the forward with a move to Saudi Arabia.
"Benzema is ready to play tomorrow, he's recovered. I agree with Benzema. Internet is not the reality. He has another year on his contract. I think it's clear," the Italian told reporters during his pre-match press conference.
"The legends of this club have to retire at Real Madrid. This is what I believe and what the club believes. But the player maybe doesn't think the same."
Ancelotti also offered his views on the season, with Los Blancos winning the UEFA Super Cup, Club World Cup and Copa del Rey, but they fell short in La Liga and the Champions League.
"It's difficult to rate yourself. What I can say is that it's been a very long season. We've worked hard and sometimes I haven't always been able to transmit a very high level of motivation," he added.
"It's not easy to motivate every three days. I've given everything I could give. I put myself on a positive note, but next year I'm going to do better."
Toni Kroos, Dani Ceballos, Luka Modric and Nacho also only have deals with Real Madrid until the end of this month, and announcements on all four are likely to arrive next week.
Real Madrid squad vs. Athletic Bilbao:
Courtois, Lunin, Fran; Carvajal, Militao, Alaba, Vallejo, Nacho, Odriozola, Vazquez, Rudiger, Mendy; Kroos, Modric, Camavinga, Valverde, Tchouameni, Ceballos; Hazard, Benzema, Asensio, Vinicius, Rodrygo, Mariano