During a "Talks at Google Presentation" Ryan revealed the agreement he had with Fox to appear as Wade Wilson/Deadpool in the controversial Wolverine film in order to get his own solo film. The result was a disaster that left many Deadpool fans upset at the portrayal of the character. Fans also dubbed him "Barakapool" because his look shared similarities to Baraka from the Mortal Kombat games. "They sew his mouth shut, let lasers come out of his eyes, and he has weird knives that fly out of his hands." The unfortunate result of his character was being an amalgamation of other characters powers such as Cyclops' optic blasts and Wolverine's healing factor.
Reynolds attempted to warn Fox "I remember saying, 'That's really going to anger some people. That's not Deadpool'," he says. "And they basically said, 'Well, you can play him or we can hire someone else to play him.' So for me, it was... I was a little bit blackmailed."
Reynolds also revealed that the 2007-2008 writer's strike caused a problem during X-Men Origins: Wolverine. Due to the strike, the producers rushed the film into production, and Reynolds ended up writing or ad-libbing most of Wade Wilson's dialogue during the early scenes of the movie.
That sounds very unfortunate but at least he was attached to the role for a long time and the result was very well done once the Merc's first solo outing arrived in theaters.
http://comicbook.com/2016/02/13/ryan-reynolds-says-he-was-blackmailed-into-playing-deadpool-in-x/