Let's break this down. The most significant fact is, for the first time ever on the show, three NFL players will compete against each other. Athletes usually go far on "DWTS" because they're used to grueling physical training. (It may be a ballroom dance competition, but at least one contestant walks away each season with a fairly serious injury.) NFL players in particular — with a couple of exceptions — have been very successful:
Taking that into account, it's fair to say that Antonio Brown, Von Miller or Doug Flutie are very likely to win. However, Flutie is 53 years old, while Brown and Miller are 27 and 26, respectively. Older contestants typically get voted off rather early — the nostalgia is exciting until it isn't anymore.
Then you've got Miller and Brown, who we're calling now as front-runners. Miller is coming off a Super Bowl win (specifically as MVP), so he has momentum. Yet that can take you only so far, like Baltimore Ravens wide receiver Jacoby Jones after he signed on in spring 2013 just after the Ravens won the Super Bowl. He placed third, losing to country singer Kellie Pickler.
That brings us to the next point: viewers, whose votes are combined with judges' scores. Was wide receiver Donald Driver really the best dancer in Season 14? Probably not, but the Green Bay Packers have a frighteningly passionate fanbase. Same goes for the Steelers, with fans all across the country. That could easily help Brown edge out Miller, which is why he's our pick for most probable winner. (Disclaimer: The author of this post is one of those Steelers fans.)
The final element: the ability to, you know, dance. Sometimes that doesn't play as critical a role as some might think (personality counts for a lot on this show). And when it comes to dancing skills, Brown and Miller are fairly matched on the field, so this may shape up to be one of the closest competitions in years.