Japanese-Canadian actor Tohoru Masamune was revealed to be the actor playing Shredder, as opposed to initial casting of William Fichtner, who was apparently rewritten as the villainous businessman Eric Sacks. On the behind-the-scenes turmoil and rewrites that plagued the film's production, Masamune tells AlternativeNation.net that he was confused himself, yet just liked the opportunity to play Shredder: For all I know they were working three different version of exactly where they were going to go with the character. I just kind of came in as an actor, and of course, if you’re offered Shredder, you’re not going to question it.
Though detractors of the TMNT reboot are quick to point out the "fact" that its a Michael Bay film, Masamune says from his own experience that Bay wasn't really that hands-on during the filmmaking process, saying "I personally did not see Michael Bay a lot, except for the occasional “this isn’t working”. Not a major thing, often a technical thing. Record at a higher bit rate, or something. He was never telling me to play my character differently." Masumune goes on to praise Bay for his eye of action filmmaking.
Masamune is very vocal about his love of the TMNT franchise, and when asked about which other franchises he'd like to appear in, he said Sin City because of his love of dark films, continuing: "I really enjoy these franchise movies… its weird because there’s a certain responsibility because of expectations surrounding a character, which is very hard for an actor because he or she can’t be held to expectations… they just need to be the character entrusted to them, they embody them, and it needs to come from them 100%. It’s very tricky. "