Prior to release, Stallone stated, "I have an idea ready to go" and "I'm going to try to do something that's quite radical". In an interview on August 15, 2010, he said that he does not have a new script yet, but "It's plotted out in my mind's eye". Stallone announced that after having dinner with Bruce Willis, he was courting the actor to take on a larger role in the sequel, possibly as a "super villain". In a recent Total Film article, Willis is quoted as saying that "Even Stone Cold Steve Austin who took two bullets in the last film, he's coming back, too. Hopefully, they'll start shooting it while we're young enough to survive" and "I talked to Sly and he's going for all the marbles this time, and he's going to get everybody in this time".

Sources said that Stallone had been talking with Jean-Claude Van Damme, Hulk Hogan, Mr. T, Carl Weathers, Vin Diesel, Dwayne Johnson, Charlie Sheen, Chuck Norris, Lorenzo Lamas, Jeff Speakman, Patrick Uro, Olivier Gruner and Ryan Seacrest about the sequel, which he intends to be "a love letter to martial arts". Stallone reportedly wants Sheen to play a CIA agent chasing Willis' crime lord character, while Norris's role will be a cameo like Schwarzenegger's in the first film. It is thought Steven Seagal will turn down the sequel, if he is asked to appear in it, because it will be produced by Avi Lerner, as the first film was.[citation needed]

Since his term as governor of California has ended, much speculation has appeared on the internet over Arnold Schwarzenegger's involvement with the sequel. Stallone has mentioned his hope to get Schwarzenegger back for a "key role" in the sequel: "If this works, I would love to get him in the next one". Schwarzenegger has yet to confirm his involvement in the film.

On April 18, 2011, Sylvester Stallone confirmed to Deadline that he will not be writing or directing The Expendables 2. However, he has confirmed he will reprise his role as Barney Ross. David Agosto and Ken Kaufman have been hired to write the script based on a story by Stallone. Deadline also went on to say that Willis's and Schwarzenegger's cameos may be expanded to larger roles. Lionsgate confirmed at CinemaCon that the sequel will be in US theaters on August 17, 2012. A teaser poster for the film was released at the 2011 Cannes Film Festival. It has been confirmed that Simon West will direct the sequel.