According to TSN:
The Montreal Canadiens let go of the goaltender who led them through their incredible postseason run and anointed Carey Price as their undisputed No. 1, as the club has traded Jaroslav Halak to the St. Louis Blues.
In return, the Habs received forwards Lars Eller and Ian Schultz.
It might be early to bash the Habs too much because they did receive prospects in return. But, after Halak did so much for Montreal in the playoffs, you would think that he was worth a little more than that. Halak will be an RFA come July 1st and the Habs do have cap issues.
This could have an indirect effect on the Rangers, but it is an unlikely one. Since the Blues acquired Halak, it's unlikely that they will retain the services of Chris Mason who is set to become a UFA this summer. However, it's unlikely that Sather will make a play for Mason as he'll probably be asking more money than Sather will want to spend on a backup goalie.