There really wasn't any room in Montreal for a 38-year old Larry Robinson unless he was willing to take on a part-time role with the team and accept the pay cheque that would come with it.
His first season in Los Angeles, the Canadiens were breaking in quite a few excellent young defensemen that were rising up through their organization. In 1989-90, their defence, anchored by Chris Chelios, was led in scoring by 23-year old Petr Svoboda, featured the first full season of young Jyrki Lumme (who was dealt at the deadline because of the surplus of d-men on the roster) got 44 games from a 20-year old Mathieu Schneider, 55-games fro a 20-year old Eric Desjardins, 68-games from a 21 year old Sylvain Lefebvre, 36-games from a 23-year old J.J. Daigneault and saw the 8-game debut of 21-year old Lyle Odelein and a ten game audition from 19-year old Patrice Brisebois.
This crop of young defenders was so promising not only was there no room for Larry Robinson, but veteran Rick Green was also dealt away that summer and the next off-season, the Canadiens traded away Chelios as well.