The post says that there are two actors under consideration at this point, but doesn’t speculate as to the second actor.
Update: Screen Rant is calling Neil Patrick Harris as the other actor under consideration. Harris has experience with the super-hero genre, starring not only as the titular villain in Dr. Horrible’s Sing-Along Blog, but as the voice of Barry Allen himself in last year’s animated Justice League: New Frontier (reviewed here). (via Fused Film)
Since DC has been busy re-positioning Barry Allen as the main Flash, it’s a safe bet at this point that the movie will star Barry.