While he made his MCU debut as a Kyln inmate in 2014's Guardians of the Galaxy, it was rumored that Nathan Fillion would have a much larger role in this year's Guardians of the Galaxy Vol. 2. Photos from the set featured posters of the actor portraying Simon Williams, causing fans to speculate that Guardians of the Galaxy Vol. 2 would mark Wonder Man’s entry into the MCU.
That didn’t happen. The background posters of Fillion as Simon Williams were James Gunn Easter eggs, and they were left on the cutting room floor, simply because they slowed the down the action.
So ultimately, Guardians of the Galaxy Vol. 2 didn’t feature an extended role for Nathan Fillion, but is that the end of it? James Gunn says it’s not, posting a new Instagram pic of a poster for a Tony Stark biopic with Simon Williams as a main character. The director also said that these posters can be considered canon in the MCU, and that he hopes that Simon Williams will soon make an actual appearance in the shared universe.
When exactly will that happen? Well, if James Gunn doesn't know, nobody does!