Here is a list of people who were cast and dropped out or auditioned and were basically the runner-up for various roles in Marvel Studios movies. It’s an interesting look at what might have been.
It’s hard to remember now but when Robert Downey, Jr. was cast as Tony Stark, he was seen as a big risk. He was well-respected as an actor but had been through a lengthy break from leading a movie thanks do drug use, court battles and rehab. Two actors were strongly considered for Iron Man/Stark during this time. Timothy Olyphant auditioned for Iron Man and publicly expressed interest in the role. Meanwhile, Sam Rockwell was so close to being cast as Iron Man, they used him as Tony Stark wannabe Justin Hammer in Iron Man 2.
Rachel McAdams was Marvel’s first choice for Pepper Potts but declined. She eventually ended up in the Marvel family when she was cast in the upcoming Dr. Strange movie.
John Krasinski was the front runner for Captain America until Chris Evans took back his original “no.”
Emily Blunt (John Krasinski’s wife) turned down Peggy Carter and then had to drop out of playing Black Widow because of a contractual dispute. She is the only actor to have rejected Marvel twice.
Tom Hiddelston dyed his hair and bulked up to audition for Thor but the producers realized he’d make a great Loki. You can see his audition for Thor on the Thor Blu-Ray. Alexander Skarsgard and Channing Tatum were also finalists. Liam Hemsworth auditioned for Thor as well, but when producers saw his brother, Chris, he got the role instead.
Josh Hartnett was a finalist for Loki until producers decided Hiddleston, who was auditioning for Thor, would work well in the role.
Mads Mikkelson was originally cast as Malekith, the main villain for Thor: The Dark World. He then dropped out to do Hannibal instead.
Glenn Howerton was the runner-up for Star-Lord in Guardians of the Galaxy, according to writer/director James Gunn.
Olivia Wilde was offered the role of Gamora but passed.
Jason Momoa was offered the role of Drax but passed because he was concerned about being typecast as a brute.
Patrick Wilson was originally cast as Paxton in Ant-Man but dropped out. Bobby Canavale was cast in the role.
Joaquin Phoenix couldn’t quite commit to doing a series of movies as Dr. Strange.