According to Jesse Spector, long term IR only provides cap relief if the team is going over the cap which the Rangers aren't. However, Spector adds that it does provide flexibility if the Rangers want to make a big splash.
Update, 8:53 p.m.:
If the Rangers put Frolov on long term IR they will get an exception for his salary opening up even more cap space.
...don't think the Stars will trade him but Richards could seriously be in play now for the Rangers.
...h/t to everyone who answered my question on Twitter.
Update, 7:35 p.m.:
Official Rangers announcement on Frolov injury and Newbury call-up.
Andrew Gross at Ranger Rants reports that Alex Frolov suffered a torn anterior cruciate ligament, a second degree sprain of his medial collateral ligament and a medial meniscus tear in his right knee last night against the Blues and will undergo season-ending surgery.
To replace Frolov, 28-year-old journeyman forward Kris Newbury was recalled from the Whale.
...i think every Ranger fan was hoping for AFro to be sent to the press box, but definitely not this way. Tough break and a tough year for AFro.
...man how far has Grachev fallen that Newbury (great call by reader Papas 1175) gets a shot over him. Although, the Rangers were probably looking for more of a grinder to fit on the fourth line.
...btw don't think I've ever seen a Rangers team this decimated by injury. Amazing job by the organization having players ready to fill-in and contribute.