I think it’s quite common for players to pick up injuries in other areas when they come back from long spells out, it’s to do with the body becoming unbalanced and subconsciously people overcompensate to protect the injured area and change gait etc. Sometimes a lot of gym work on a certain area, muscle or group of muscles can lead to another area being neglected or becoming proportionally weaker as well.
The real question is whether this could have been avoided had Browne spent another week, or few weeks, slowly upping the intensity in training, but I guess we’ll never know that.