You must mean a rite of passage.
Sounds like a remnant discretionary option that may have been passed down from the days of cigar-chomping, fedora wearing, crusty owners and their executioner GMs. Yet there are GMs who probably don't even care about such a thing and there are probably a good number.
Would have preferred to see Fleury get a number that had not been worn recently. I just find it a tad annoying when a new player is sporting a jersey that used to be filled by another player until as recently as last season, when that number had been identified with the prior player over several years.
There ought to be a little distance between the time such a number is re-assigned just so that you get the impression of a new beginning for the new player who adorns it. But hey, first world problems, right?