Ubisoft chose a new voice actor for Sam Fisher because Splinter Cell: Blacklist is the first in the series to rely so heavily on motion-captured performances.
Creative director Maxime Béland told IGN that for past games, Ubisoft used three different performances to capture the whole of Sam Fisher - a voice actor, a facial animator and a motion capture artist.
"On Blacklist we knew that we wanted to raise the bar of our scripted events, of our cinematics, and to do that we knew we had to go to performance capture," he said.
"The difference between motion capture and performance capture is that with performance capture, you're capturing everything at the same time.
"So we had one actor doing the body, the voice and the face. We have a camera that's recording all the facial animations so right there, because you're capturing a true actor's performance, and the level of quality is raised instantly."
Béland said that Ubisoft faced the problem of needing someone who could do "not only the voice but also had the physicality that Sam Fisher has".
"That's why we had to go with an actor that was able to do that, so we found Eric Johnson," he concluded.
Johnson replaces Michael Ironside, who had voiced Sam in all other games.
Splinter Cell: Blacklist is coming to PC, PlayStation 3, Wii U and Xbox 360 on August 20 in North America and August 22 in Europe.