Deadpool will be released next February but we don't have much casting for the film at the moment. TheWrap has an update with news that both TJ Miller (Big Hero 6, Silicon Valley, Cloverfield) and Ed Skrien are being looked-at for major roles in the film. Miller's role is said to be comedic of nature, which I assume means it could be Weasel or Fox's version of Bob Agent of Hydra.
Ed Skrien on the other hand is said to be the up for the villain role. We have no idea who that character could be since the major script rewrites, but I would take a guess that Taskmaster or someone like that is a strong candidate. Skrien is best known for his roles in Game of Thrones and Transporter: Legacy, both of which were extremely action-heavy characters. This leads me to believe he very well could be Taskmaster or another extremely psychical X-Men villain.
Here's why I believe Taskmaster is a strong candidate to become a major villain in Deadpool.
At one time Fox tried to have a Taskmaster film put together by Joe Carnahan, who later developed a gritty Daredevil reboot for them as well. My assumption is that Fox still holds the rights to the character, since we haven't heard anything about him returning to Marvel. The Marvel villain has tangled with Deadpool on many occasions and seems like a threat that would outside the mutant world. He's also one of the more recognizable villains Deadpool has clashed with over the years.
Nothing says it couldn't lead to him getting his own spin-off eventually, since we know Fox did want to give the character his own movie. Plus, after all the extensive rewrites that the original script underwent after it leaking a lot stuff could have been scrapped.
Carnahan confirmed to SuperheroHype back in 2010 he was indeed working on the Fox movie project, adding he'd like to make a Juggernaut film as well. His vision for the Taskmaster film was a mix of Punisher, Deadpool and Blade, too bad it never came together. Joe is currently attached to direct an adaptation of Mark Millar's comic Nemesis and his successful series Blacklist airs on NBC.
"For Alex (Young, producer of "The A-Team") I was going to do Taskmaster. Originally I wanted to do Juggernaut ’cause I had a really good take on that, and then Taskmaster was something we talked about, and I haven’t discussed it with him for ages, but I would love to get back in. I love the idea of a guy with photographic reflexes, he can see something and repeat it, I thought that was such a cool idea. I think there’s a Moon Knight series where he just beats the sh*t out of Taskmaster and kind of ruined him, and it’s a cool character. I think it might be one of those Marvel characters you really need to reimagine because he’s got the whole skull and cape—it’s a bit grandiose I think—but it would certainly be a cool thing."
"It was very much in the realm of the Punisher," he continued. "It’s kind of funny because it’s almost what they were going to do with Deadpool, that same sort of smart-ass thing, before they went the way of–and I know that there are fans that hated Fox for doing that whole thing with Deadpool and Reynolds in ‘Wolverine’–but you have to create that differentiation. I think at least Taskmaster, he’s so below the radar. He’s even below where Blade was considered a B-tier Marvel character, this guy is even lesser-known. It would be a lot of fun to write it as a series and then see what came from there."Here is the sizzle reel Joe Carnahan made for his Daredevil reboot pitch which was never made it past concept. I assume some of this helped Marvel consider a darker tone for their upcoming Netflix series dropping in April.