In some essence, Pollux represents the classic sci-fi camp material that The Flash leans on so heavily in successful depictions. Nevertheless, his story is both trope-y and outlandish enough to likely keep him far away from James Gunn's DC Universe. Of course, a cameo appearance is possible thanks to multiverse shenanigans, but it's hard to get around the idea that only a small percentage of modern viewers would have any clue who this angry blue guy is supposed to be. It might just be too confusing to work.
Outside of Pollux's very weird story in the '90s "The Flash" series, there's another major element lessening his chances of popping up in James Gunn's fresh DC Universe. Simply put, there's a ton of other villainous speedsters to choose from that would be a far more popular pick for a new adaptation of the Flash mythos. There's little chance that Pollux is going to get a shot at The Flash before Reverse-Flash or Hunter Zolomon show up, and he may not have enough distinguishing characteristics to warrant an appearance in the same universe as these big names.
Still, not all hope is lost. 2023's "The Flash" movie, which will simultaneously serve as the chronological swansong of the DC Extended Universe and the jumpstart for Gunn's film universe reboot, is set to feature an adaptation of a deep-cut speedster from The Flash's history. With Pollux occupying a similar niche status to this particular character, it means that the blue-hued Flash clone has at least a non-zero chance of showing up down the line. Things will probably be clearer on that front once the future of The Flash beyond the 2023 movie is revealed.
