It's learned Benedict Cumberbatch, who actually had a scheduling issue and almost couldn't commit to Doctor Strange, also has a conflict for filming on The Avengers: Infinity War.
No worries though, as Broadway star Aaron Lazar has Cumberbatch covered and will be used as a stand-in while filming on Avengers: Infinity War commences in Atlanta, Georgia.
It's further noted when Benedict Cumberbatch is finished filming on The Current War that Marvel will reshoot the Avengers: Infinity War scenes where Aaron Lazar can be seen.
A source close to Disney also notes, “They are not digitally superimposing Cumberbatch onto another actor’s performance,” which probably means Marvel wants to use Aaron Lazar's own performance as Doctor Strange to give the role some authenticity and help out the other actors during the Doctor Strange scenes in the film.
Marvel Studios and Kevin Feige pushed back production on the recent Doctor Strange movie to accommodate Benedict Cumberbatch's schedule because they felt so sure of him as portraying Dr. Stephen Strange.
With The Avengers: Infinity War having so many characters, Marvel could have easily rewritten Doctor Strange out or even vastly reduced Benedict Cumberbatch's scenes to a cameo; so with Feige using Aaron Lazar temporarily, it's nice to see Marvel Studios sticking by Cumberbatch and their actors and story.
The Avengers: Infinity War has a May 4, 2018 release starring Josh Brolin as Thanos. Marvel Studios has yet to officially announce the cast, but the following are thought/confirmed to be a part of the movie: Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Scarlett Johansson, Jeremy Renner, Cobie Smulders, Samuel L. Jackson, Sebastian Stan, Chris Pratt, Zoe Saldana, Karen Gillan, Dave Bautista, Bradley Cooper, Vin Diesel, Paul Rudd, Elizabeth Olsen, Paul Bettany, Chadwick Boseman, Benedict Cumberbatch, Benedict Wong, Tom Holland and Brie Larson.