Allow me to preface this by mentioning that there's no need for panic and concern over whether or not Alex Pietrangelo will be signed by the Blues. He will be. The concern in the situation is obviously about term. Will they, seeing as Petro had a down year last season, offer him a couple-year bridge deal a la the Habs and P.K. Subban, or will they give him Drew Doughty money ($7 million a season for eight seasons)? That's really the question that fans should be wondering about and that the front office should be worrying about.
Petro will stay a Blue. He'll probably stay a Blue for a long time. But, like with any other contract talk, it takes a while to agree on how much he'll get paid. It happens. No one on either side of the discussion is freaked out about his future in St. Louis, and no one else should be either.
The Blues are being practical about this. They know that talks have taken months, and there doesn't seem to be a definite end in sight. There's a strong chance, regardless of how much Pietrangelo needs to be there, that he isn't ready for training camp or the pre-season. That is absolutely the only reason that the Blues need to have a plan B for camp. You need a full set of defensemen to practice, and they need someone with Petro's ability there to make the practices accurate. Barring being able to find someone Pietrangelo-esque (good luck with that) you need someone who is at least a reasonable hole-plugger.
Enter Ryan Whitney.
Late of the Edmonton Oilers, Whitney is likely to be invited to the Blues' camp on a pro tryout. Will he make the team? No. There's nowhere to put him except on the Wolves. He hasn't played close to a full season since 2007. This is nothing more than a stopgap until a contract gets signed, and GM Doug Armstrong made that perfectly clear.
It's hard to not expect players like Whitney and fellow UFA defenseman Ron Hainsey (who has also been bandied about as a temporary fix) to wind up with a team at some point. They have gas in the tank, especially Hainsey, whose unsigned status is probably owed more to his role in the lockout talks than anything else. But that gas won't be burned in St. Louis.
Like petrol, Petro doesn't come cheap, but he'll still be affordable.