I've noticed this one for a bit now.
Seems that, with high consistently, all injuries listed from Quarters 1 through 3 are designated as "should be able to return". However, with equally high consistency, injuries in Quarter 4 are never designated as "should be able to return"... Though some players inevitably do return and play.
Not sure if it's a glitch with the PBP logic, or an actual injury bug.