The current slate of films listed for the Marvel Cinematic Universe does not include "Iron Man 4," and as previously reported, the film is likely to premiere by 2020 or even beyond that date. According to a report from Parent Herald, this may cause Marvel Studios to eventually put Robert Downey Jr. to the sideline and let someone else don the suit.

This doesn't necessarily mean someone is replacing Downey Jr. as Tony Stark. The film could still have Tony Stark as one of the main characters but instead of him being the one inside the suit Stark, he may end up giving the suit to someone else, most likely someone younger that could star in many future Marvel films.

Fans will point out that this is very similar to how "Ant-Man" saw Hank Pym (Michael Douglas) passing the Ant-Man suit to Scott Lang (Paul Rudd). As Hank got too old to don the suit and physically go out and fight, he remained a pivotal character who trained Scott until the latter was capable of fighting on his own.

Ever since "Iron Man 3" was released, there have been rumors that the Iron Man suit will be passed to someone else and the most mentioned candidate has been Ty Simpkins' Harley Keener. Simpkins was still young by the events of "Iron Man 3" but will be in his late teens by 2020, ensuring he will be old enough to be Tony Stark's successor.

The report also points out that Downey Jr. is getting "tired" of the role. By the time 2020 rolls in, he'll have played the role for well over a decade.

Unfortunately, nothing has yet been confirmed by either actor or by Marvel Studios. Downey Jr. is still set to be Iron Man in the upcoming "Captain America: Civil War" and is rumored to appear in the solo "Spider-Man" movie before he makes another appearance in the two-part "Avengers: Infinity War" films.