Nope, they increased the squad size from 15 to 17. The two extra are 2 way contracts, can be rostered with the team for 45 days during game play. No player movement, no IR designations. Player tweaks an ankle and will be out for 2 games, you pull that guy up and have him there. They aren't there all the time, becasue they want them playing games and getting reps so they spend majority of the time in the G.
Edit: Best comparison is when the rosters increase the last chunk of the season in MLB (or is that just the playoffs?)