What do you think caused these changes in NHL player Sidney Crosby's nose? (Comparing 2010 to Later pictures) (photos)

I do not think there has been any change in the nasal shape.  The photos posted all vary greatly in terms of camera angle, lighting and most importantly facial animation.  Nostril show will be highly influenced by all of these and especially by facial animation in which any facial 'pose' with tooth show indicates smiling or drawing the upper lip up in which case the nostrils will flare.  Photography is a very average depiction of 'real life' at best and for one to make accurate comparisons, standardized conditions need to exist between the 2 photos being compared.  Mario J. Imola, MD, DDS, FRCSC, FACS.

You are definitely astute with your nasal analysis.  Hockey players easily succumb to injuries to the nose based on the nature of the game.  Therefore, common traumatic injuries result in nasal bone deviations and humps, loss of cartilage support causing the nasal tip to  drop and nostrils tend to retract upwards. These changes are addressed with functional rhinoplasty maneuvers that include cartilage grafting.  This is a specialized field and I recommend consulting with a board certified facial plastic and/or plastic surgeon regarding any nasal reshaping procedure.