Warner Bros.' growing DC Extended Universe briefly introduced movie-goers to The Flash in Zack Snyder's "Batman v Superman: Dawn of Justice" before the character appears in the planned two-part "Justice League" series and his own standalone film. The scarlet speedster will be played by Ezra Miller, who you can all tell is not Grant Gustin, star of the popular CW series "The Flash."

Some believe that Snyder should have gone with Gustin, though Warner Bros. has always maintained that their film and television properties are separate. One vocal defender of Gustin is his "The Flash" co-star Tom Cavanagh, who recently went to bat for the young actor.

"Here's what I'll say about him not being The Flash," he said. "The first thing is that for Zack Snyder to say 'that's not really the universe that we're building,' it's excruciating for an actor. Because you're like, 'Uh, what about acting?' He's a clean-cut guy and winning, yes, because he's acting that. He's not Barry Allen. He's Grant Gustin. He created that thing. If you want [your Flash] to have long hair and be a slacker, believe me, Grant can play that. He makes it look easy and makes everyone think that's what he is because he's an incredibly skilled talent. That's why he has that job. That's why people like the show.

"If Zack Snyder were to read him for [The Flash], he would be shocked. It's crazy for a big-time Hollywood director to say 'that's not the universe.' It's a huge misstep on his part. If you're a director, and you're worth your oats, then you should be able to, given an actor with talent, mold him into what you want, and Grant could do that."

Cavanagh's point is well taken. There is already an established, well-liked star in the role that fans would like to see. From a continuity standpoint, it would make sense for Gustin to get called up to the big leagues in the DCEU.

But in defense of Snyder, the film/television universes are different. "The Flash" TV show, for all its bells and whistles, is a superhero soap opera aimed at teenagers and young adults. There's nothing wrong with that, but it stands in stark contrast to the grounded and realistic vibe WB is going for.

What do you think? Should Snyder have cast Gustin as The Flash? Let us know in the comments below.

Follow Brandon Katz at @Great_Katzby