Most physiatry employers start to look for a new hire in October or November to coincide with the AAPMR Job Fair. For residents, you can start to look as soon as your senior year starts although many employers aren’t willing to wait for a year. However, more and more employers now who are in areas that are not as generally desirable or include inpatient rehab work (which is harder to fill) will wait a year.
I don’t recommend passing your cv onto recruiters until you’ve heard about a physical medicine and rehab position and have an interest in it. Some recruiters will pass your cv on without your knowledge and then you might receive a call from an employer without any foreknowledge.
Don’t worry about being too late! Although you may not have as broad a range of practice opportunities available, there are many good opportunities available as late as the spring of your senior year. Also, don’t accept a practice opportunity that is not the best for you just because you’ve set a personal deadline of say December.