Enstrom is not taking Oystrick's spot. As it is, it's Enstrom's spot to lose, he's the best choice for the open spot. Oystrick will REALLY have to impress at camp to have a shot at a roster spot.
That said, I think Oystrick could compete for a spot in the next couple years. When he started with the Wolves last year, he was an excellent offensive defenseman tight off the bat, but his defense was lacking. As the season went on, he really made some nice defensive plays, especially on opponent break aways. I can see him being a second pairing D-man/PP QB in the future.
As of now, you have Enstrom, Popovic, Oystrick and Lewis all as possibilities. Enstrom may need some adjustment to the smaller ice surface. Lewis has been described as NHL ready from a skills perspective but is not conditioned for an 82 game campaign as he saw only 24 NCAA games last year.
There's a lot of competition for a spot on the blue line, and with Zhitnik, Havelid, Exelby, Klee and McCarthy all signed, it looks like only one spot is open.
It isn't Enstrom's spot to lose and there are several people ahead of both him and Oystrick.
I think that the general consensus would be that, assuming he is in shape and has a good camp, Pilar would be in the top 6 or 7.
These 4 are in:
These 3 are next:
These two have the potential to make it but probably won't be in the line-up opening night: