Tony Stark – aka Iron Man – is one of several characters heavily rumoured to exit the Marvel universe in the upcoming movie or its as-yet-untitled follow-up.
In a new interview, Russo appeared to choose his words very carefully as he indicated that nobody will take over the part if and when Downey Jr steps aside.
“There is nobody who can take over Iron Man from Robert,” he said, according to Hindustan Times. “I don’t think the audience would accept that.
“He never mentioned to us about leaving Iron Man, but it will happen at some point of time.”
He went on: “He can’t play the character forever. I am sure there are lots other things he wants to do in his career.
“But he loves playing the character, I know that, and we love working together. We will see where it goes from here.”
This comes after Benedict Cumberbatch hinted that his own character, Doctor Strange, could be among the fatalities – so soon after joining the MCU.
Alluding to Thanos, he told MTV: “There’s lots of threats coming his way. He holds the Time Stone around his neck for a part of this film.
“We know someone is coming to get them for a big glove.”
When the interviewer said he’s unlikely to meet his demise, Cumberbatch added: “It might not be. It says you’ll see Doctor Strange again at the end of the first one and you have.
“You’ve seen him in Thor: Ragnarok and you know he’s in this one. Doesn’t mean there’s gonna be any more of him, so you’ll have to wait and see.”
Talk also continues over where exactly Hawkeye (Jeremy Renner) is, given that he has not appeared in any trailers or posters so far.
“We keep saying, ‘Patience is a virtue,’” Joe Russo said this week.
“We did not forget the twice-nominated Jeremy Renner. We cooked up a story for him that is a little bit of a long play. Not a short play.”
Avengers: Infinity War is out on April 26 in the UK.