With this summer's release of Spider-Man: Far From Home, Phase 3 of the MCU will come to a close. The third phase of the cinematic universe is likely the most ambitious yet, with some the franchise's biggest movies and crossovers helping to bring an end to the so-called Infinity Saga.

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Phase 3 also saw some new and exciting characters being brought to the MCU for the first time. This included heroes that fans have been waiting to see on the big screen for years, like Doctor Strange, Black Panther, and Captain Marvel. This meant lots of new actors were added to the growing universe, many of which will be the new faces of the MCU. But with some of the alternate casting choices, Phase 3 almost looked very different. Here are some of the actors nearly cast in Phase 3 of the MCU.

Chandler Riggs As Spider-Man

Chandler Riggs as Carl Grimes in The Walking Dead

One of the most exciting aspects of Phase 3 was Spider-Man's long-awaited introduction into the MCU. One of Marvel's biggest heroes, the studio was able to reach a deal with Sony that allowed the wall-crawler to share the screen with the Avengers. With his debut in Captain America: Civil War, many of Hollywood's young upcoming actors auditioned for the role, including The Walking Dead's Chandler Riggs.

Given that the MCU wanted to go for a high school-aged Peter Parker, Riggs felt like a good pick, but he confirmed on Twitter that he didn't secure the role. Tom Holland would eventually be cast and make the role his own.

Sterling K. Brown As M'Baku

Randall discourages a patient against pursuing love on This Is Us

Sterling K. Brown is quickly becoming one of the most interesting actors working today with roles in This is Us and The People vs. OJ Simpson. He also got a lot of attention for his brief but memorable role as N'Jobu in Black Panther. As the conflicted father of Killmonger, Brown brought a lot of intensity to his small part. But he was originally considered for a more prominent role.

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Brown said he had a memorable audition for M'Baku, the leader of the mountain tribe, but director Ryan Coogler decided he would be better suited for the more subdued role of N'Jobu. M'Baku would be played by Winston Duke, who became a breakout star from the role.

Joaquin Phoenix As Doctor Strange

Joaquin Phoenix has a reputation of taking on intense acting roles and being very selective about the projects he selects. This has meant that he has chosen to turn down quite a number of big movies, including a few superheroes. One such role that Phoenix reportedly declined was the Sorcerer Supreme himself, Doctor Strange.

Set to be one of the future leads of the MCU, many top actors were considered for the role before Benedict Cumberbatch took the role. Phoenix admitted to being a fan of the Marvel movies, but he thinks everyone is happier for how it turned out. Instead, he'll try his hand at playing a villain in Joker.

Matthew McConaughey As Ego

Matthew McConaughey in Serenity 2019

Not too long ago, Matthew McConaughey was mostly known for forgettable romantic comedies. Then he had an unexpected career resurgence with roles like Dallas Buyers Club, True Detective, and Interstellar. In the midst of this period of great roles, McConaughey was offered the role of Ego in Guardians of the Galaxy Vol. 2.

McConaughey says that he was a fan of the first film but passed on the part because he felt like he would just be an addition to a proven product. He chose to do The Dark Tower instead so he could create his own role. Kurt Russell played Ego quite effectively in the sequel.

Keanu Reeves As Yon-Rogg

Keanu Reeves is having a very good year. John Wick 3 proved to be an excellent addition to the action series, he is voicing one of the new characters in Toy Story 4, and the Internet can't stop talking about what a great guy he is. However, 2019 was almost even bigger for him, as he was close to being in the widely-successful Captain Marvel.

RELATED: Captain Marvel: Yon-Rogg Sees HIMSELF As Supreme Intelligence In Deleted Scene

Reeves was very close to taking the role of Yon-Rogg, the main villain of the film, but was forced to pass because of John Wick 3. Jude Law took over the role and Reeves has already been linked to another MCU role in the upcoming The Eternals.

Matt Damon As Mysterio

The MCU had been very careful not to use actors in more than one role as a way to maintain continuity. There have been a few exceptions to this, but Matt Damon was almost one of the most notable double-dippers in the cinematic universe. Very memorably, Damon popped up for a cameo in Thor: Ragnarok as an Asgardian actor, and he was also pursued for a major role in this summer's Spider-Man: Far From Home.

It's unclear which role Damon was up for, but it's a good guess it was probably Mysterio. Damon turned down the part—perhaps to maintain continuity—and Jake Gyllenhaal was cast in the mysterious role.

Amandla Stenberg As Shuri

Amandla Stenberg is a very talented young actor who audiences first noticed as Rue in The Hunger Games. She has continued to build a strong career and seems poised to break out in a big way with her buzzed-about performance in The Hate U Give. Stenberg almost had her biggest role to date when she almost appeared in Black Panther.

Stenberg auditioned for the role of Shuri, sister of T'Challa and princess of Wakanda. Interestingly, she stepped away from the role because she felt it wasn't right for a bi-racial American to be playing an African character. Letitia Wright eventually got the role and stole the show.

Ethan Hawke As Doctor Strange

Ethan Hawke as Ellison Oswalt in Sinister

When it came to casting the role of Doctor Strange in his first solo film, Marvel seemed very interested in the kinds of actors you wouldn't normally think of as starring in a comic book movie. Like Joaquin Phoenix, Ethan Hawke was most known for smaller films and generally avoided the action hero roles.

RELATED: Doctor Strange 2 May Film Next Year, According to Benedict Wong

Hawke said that he felt very tempted by the idea of joining the MCU but ultimately decided against it because the extended contract would prevent him from taking interesting roles. The infamous MCU contracts have probably dissuaded many fine actors from joining the cinematic universe.

Timothee Chalamet As Spider-Man

Timothee Chalamet is one of the most talked about young actors in the business today. He is still in the early stages of his career, but he's already found immense success with roles in Lady Bird, Call Me by Your Name, and Beautiful Boy. Before all that success, he was one of the many young actors considered for the MCU's Spider-Man.

Chalamet says he read for the role twice but was unhappy with his own take on the part. While losing such a role must have been hard, Chalamet's star continues to rise and he'll soon lead his own franchise with Dune.

Mark Hamill As Vulture

It's a shame that such a talented and entertaining actor like Mark Hamill can't seem to escape his iconic role as Luke Skywalker simply because he was so good at it. Hollywood has had a hard time seeing the actor in another role since then, which is certainly our loss. Hamill himself has tried to break out of the Skywalker box and even pursued a role in Spider-Man: Homecoming.

While it's unclear if Hamill was in the running for the role, he publicly stated that he had hoped to play Vulture in Homecoming, joking it was one of the few villain roles for senior citizens. Michael Keaton was great in the role, but we'd love to see Hamill join the MCU eventually.

NEXT: Casting The MCU's Green Goblin: Colin Farrell Would Be The Perfect Norman Osborn