Per Andrew Gross, Ryan Callahan and Carl Hagelin both suffered torn labrums in their left shoulders, and will undergo surgery to repair the injuries. The injuries will sideline each player for 4-5 months, which gives both of them a September-October return date. With that timeframe, both would miss training camp, the preseason, and possibly the start of the season.
Luckily for the Rangers, this timetable does not mean they will miss significant time due to the injuries. However, this is a major shoulder surgery for both players.