Mason ran out of gas at mid season. end of story. it wasn't the whole "Pop broke his confidence and rhythm ba playing him wrong". Mason would also have struggled at SG. IMO when Pop tried to play him as back up PG, his first intention was to find a role to reduce the workload for Mason. defending some back up players is usually less exhausting than defending starter SGs. IMO Pop just tried to save Mason's season, he knew very well during February, that Mason is going to fall apart.
however, the secret for a successful season for Mason will be a special endurance programm over the summer and reduced minutes, not much more than 20MPG.
as we heard some weeks ago, Mason has lost weight and works hard every day. and point two will be easy to manage, with RJ, Manu back and also the addition of Bogans.