Cue up the Unsolved Mysteries theme music. Where is Robert Stack when you need him? With this week's hiring of Dave Hakstol to resurrect the Flyers franchise, which is stagnating in mediocrity, we are truly in a period in which there are plenty of questions and few definitive answers when it comes to the four head coaches in this town. The coaching scene in Philadelphia professional sports is a mystery.

While Hakstol is a complete unknown, I applaud the move and the out-of-the-box thinking. Sure, you have the connection with Ron Hextall's son, but if that's your beef, you're reaching big-time. You can't kill the Flyers for this move and also kill them for hires in years past when another "Flyers" guy was tabbed head coach.

Hakstol won 61 percent of his games while with the University of North Dakota and, during an 11-year stretch, reached the Frozen Four six times, including the national final in his first season.

I'm exhausted by the retread approach, hoping to rekindle magic with a slightly-above-.500 coach. Enough of the "Flyer" mentality and citing flimsy rationale such as his previous run as a player in South Philadelphia. Coaches grow on all sorts of trees, worldwide, and I for one am glad the Flyers took this approach and plucked one from a field I've never walked in.

I know hardly anything about this guy. I don't know what he will attempt to do. I haven't the slightest idea whom he will build around and whom he will want to jettison out of here. It's a mystery and one that I look forward to seeing morph into a solution.

The head coach of the other Wells Fargo Center occupant, the Sixers' Brett Brown, is also a mystery. Having hosted the Sixers Radio Network postgame show for the past two seasons, I tend to believe he will wind up being a very successful coach, if GM Sam Hinkie supplies him with the necessary tools and decides to end the tank-a-thon and flipping of assets and the process of stacking second-round picks.

Brown has done a tremendous job with limited talent. But success will be defined by eclipsing 25 wins in 2015-16, approaching .500 and making the playoffs as an eighth seed in the following year, and then by 2017-18, being competent enough to make a playoff push in May. At least that's how I'd define success in the short-term Sixers future. Can that actually happen? Your guess is as good as mine. It feels as if he's a good coach, but still a mystery with success TBD.

That brings us to Ryne Sandberg. I won't waste much time on the Phillies. Despite a recent six-game winning streak, I am still perplexed by what "Ryno" actually is. It's beyond difficult to evaluate the job or lack thereof he has done, thanks to an inept GM in Ruben Amaro Jr.

I also see the value of a baseball manager dwindling in this modern baseball climate. Have you seen the salaries of baseball managers, compared to coaches in the other three professional sports? Roughly 200 games a year and they don't make much, especially considering the enormous television contracts in the sport.

We all saw what transpired Sunday night in Miami. A general manager leaves the suites and comes down to the dugout with zero experience? You could bring in Tony LaRussa, Joe Maddon or Norristown's own Tommy Lasorda and this team would be exactly what it has been the past few years.

Maybe we will never see what Sandberg has, as a return to relevance might not happen until 2020, but to this point, he's a mystery with what he has been given to work with daily.

That leaves us with the most known commodity in Philadelphia sports, Chip Kelly. Jeffrey Lurie found a good coach to bring the Eagles back to respectability. Ten wins in 2013, a division title, and a home playoff game have been added to Kelly's Wikipedia page.

Regression the following season has also been added to his resume. In a pivotal third year, after a litany of transactions, racism allegations and bringing back Tim Tebow from football obscurity, you can be guaranteed of one thing: Trying to handicap 2015 is a total mystery. It could very well be a boom or bust season. This is one that will define Kelly and his tenure in Philadelphia forever.

The city has become an experimental marketplace for pro sports, a think tank of some sorts. The guinea pig for multiple tanks in hoops, to college head coaches from the football and hockey ranks journeying to the pro level. Should it be this way? Will it pay dividends? Let's hope the mysteries get solved soon.