At this stage of the season, with 3 rounds left, the infirmaries seem to be filling. Those wards are certainly not the exclusive domain of Shore Rugby, despite the impressions from reading this thread. All teams to some greater or lesser extent, have already had to cope with filling vacancies in their top flights. But the timing of the injuries, and the "key-ness" of the players hurt, is as arbitrary as anything else in life.
Losing Tom Wright and Blaise Barnes for the season, even with the vaunted depth of Joe Boys Rugby, puts them at a disadvantage in closing out their season in the way they'd like. That won't be assisted if they also lose Aus Rep hooker and Joeys Captain, Tom Horton, hurt at Bellevue Hill yesterday.
The Riverview coaches pulling Macgregor from the field yesterday, especially as the game sounded well won by then, is just plain sensible, both as to player welfare and to team management given how important Macgregor is to the Blue and White.
I haven't done any statistical analysis (will leave that to others far better qualified), but there does seem to be an inverse correlation between injuries to first choice players and their teams' current ladder positions - New on top on that metric, Shore at the other end, and the rest filling their respective spots accordingly. (Coincidentally, it'd seem the same thing is panning out in the QLD GPS 1st XV Rugby Comp.)