I don't know how you can say that given his past success. I know he had a bad year or two, but that happens (especially when the team you're on isn't exactly a defensive juggernaut). He's not a superstar and I don't think he is the answer to our long-term goalie situation, but I do think he's a better option that Elliot and Neuvirth. It is bizarre to me that a goalie that can't stay healthy (and also recently put up a season of .891 save percentage) is an option along with another goalie that has at best been inconsistently mediocre over the course of his career, but Mrazek is not an option because in 17 games he played poorly on a team with a defense that everyone agrees is not good. You don't want to give up the third to sign him...that's an understandable position. You think Mrazek isn't an NHL goalie despite the fact that his career numbers are comparable to the other two goalie options (almost identical SV% to both, better GAA than Neuvirth) doesn't really make sense to me, unless you are also saying that the other two are not NHL goalies, in which case I would still disagree but at least your position would be more defensible.
Elliott and Neuvirth are fringe NHL goalies at this point. I'd be ok with Elliott as my backup; Neuvirth is too unreliable.
But the fact is that Mrazek put up an .891 save percentage in the exact same environment that AHLer Alex Lyon put up a .905.
Mrazek lost his starting job in Detroit for a reason. His last two seasons have stunk. I mean, at least Neuvirth rebounded from one bad season. But when your last two you are near the league bottom in save percentage, it's a lot harder to consider it an outlier. He was .901 and .902 total the last two years, .891 with the Flyers, and he even stunk in 10 games of international play last year, with an .894.
There's no indication he's going to rebound after his last two seasons -- certainly not enough to give up another 3rd. Like I said, he has tons of flaws in his game, and most likely the NHL has figured him out. And his small size and all-over-the place style simply don't jive with today's NHL.
How many major league pitchers have you seen have you seen have a good season and a half after a call-up, but by their third season the league has a book on them, or they lose a MPH off their fastball, and they're never good again? Tons.
I think it's a fool's errand to blindly hope Mrazek puts up similar stats as 3 seasons ago, when his numbers have been bad the last two seasons and just by looking at him you can see all the flaws in his game.