2016 will be an important year for 20th Century Fox's Marvel movies. The studio will unleash Apocalypse's cinematic debut in X-Men: Apocalypse, while Merc With a Mouth Wade Wilson (a.k.a. Deadpool) and the card-throwing X-Man Remy LeBeau (a.k.a. Gambit) will headline their own spinoff films. 2017 is going to be just as big for some fans because it'll feature Hugh Jackman's final performance - or so he says - as the most popular X-Men character Wolverine.
Since Fox has three big comic book projects on the horizon, not much has been revealed about Wolverine 3 yet. At San Diego Comic-Con 2015, Jackman teased fans about Old Man Logan - a widely loved Wolverine comic story by Mark Millar and Steve McNiven. Then, the actor took to Twitter and asked fans what they want to see in his final outing as Wolverine. The most common answers: his archenemy, Victor Creed/Sabretooth, and berserker rage (which is when Wolverine unleashes his adamantium claws and truly lets loose).
Liev Schreiber portrayed the bloodthirsty villain in X-Men Origins: Wolverine, and he's since implied that he would be open to becoming Sabretooth once again. During the above interview with Jimmy Fallon, Schreiber was asked if fans could expect to see Wolverine vs. Sabretooth in the next movie. The actor's good-humored response (as seen below) shows that he's not involved with the project yet, but that he is open to the idea:
"I don't know if I'm invited, but what I heard was that the storyline is Old Man Logan. And when I heard that, I thought, 'Well, you know... there's Old Man Logan, there could be Old Man Sabretooth.'"
He then went on to joke about the two being so old that they need walkers, so it's possible this was more of a lighthearted comment, and not something to be taken as a tease that he really wants to be involved. Still, with Jackman being aware of the fact that many fans want Victor Creed to return - and the fact that Creed is Wolverine's most well-known enemy - it isn't far-fetched to believe that the studio is at least considering working Sabretooth into the script, or has possibly even reached out to the actor about the idea. Schreiber didn't shoot down the idea of being involved, so it looks like fans hoping for a Sabretooth appearance might get what they want. The movie's still in the early stages of development, after all.
While the Old Man Logan comic may not involve Sabretooth - beyond an illusion, that is - that wouldn't prevent the movie from using the character. For example, The Wolverine was based on Frank Miller and Chris Claremont's Wolverine limited series (which is a great read, by the way), but the film made several blatant changes to the narrative and brought in new characters (e.g. Viper, Kenuichio Harada, "Silver Samurai").
Seeing as Old Man Logan heavily incorporates several Marvel characters that Fox doesn't have the rights to, it's possible that the movie could have Sabretooth as the big bad, or maybe one of the villains Wolverine encounters in the story. Old Man Logan did include several villains, and if this is truly Jackman's last time playing Wolverine, it's hard to believe they wouldn't want to include as much fan service as possible. If the script stays remotely true to the comic (i.e. villains have taken control of North America), then the movie could absolutely have nods - or even appearances - by several other Wolverine villains (e.g. Gorgon, Cyber, Omega Red, etc).
Fantastic Four is currently in theaters; Deadpool opens February 12, 2016; X-Men: Apocalypse on May 27, 2016; Gambit on October 7, 2016; Wolverine on March 3, 2017; Fantastic Four 2 on June 9, 2017; and some as-yet unspecified X-Men film on July 13, 2018. The New Mutants is also in development.
Source: Jimmy Fallon