I am back from my 12th or 13th injury in the last 3 or so years. This last took almost 3 months. I tried very gradually some jogging on grass barefoot, some in flats, and some in normal shoes.
It may work for some, mostly with good mechanics, and even some with not so great mechanics, but this theory about orthoses and cushioned shoes being counterproductive is not yet supported. A lot of good runners never do this, and I am now possibly injured again (after already being out 3 months) because I tried the advice of some people on the message board who I do not even know over the advice of a doctor who has actually seen me.
My mistake, but to anyone else considering it, be forewarned, you should listen to your doctor and those who have seen your mechanics. Use what works, not what you are given on a message board by strangers. Injury sucks, and training in racing flats will not change that.