That thinking would certainly seem to make sense, and you could be a lot closer to correct than I am. We will certainly find out soon enough though.
As you stated, Brace could certainly benefit from the lessened competition this year, and has shown something when healthy in run support. That, and a cheap enough rookie deal with one last year could equate to enough of a reason for keeping him again.
However, if there are other circumstances in the equation, that may certainly change things and he may indeed need to step up to keep his spot here.
To be honest, I do not feel as though he 'needs to make great strides' to keep his job, but I do feel as though he will have to step up a bit. My statement was more of a general term that was speaking of all of the players like Cunningham, Brace, Pryor, etc, in the fact that they 'need to take a step or two to keep their job and prove their doubters wrong.'
Not trying to nit-pick or mince words, just trying to say that I do not believe that he necessarily 'needs to make great strides.' Maybe a singular 'stride' would be sufficient.
At any rate, as I said, the fact still remains that you could be quite closer to the truth in this one, and what you say certainly has some good merit. We'll have to see it play out in TC, and it will definitely be something to keep an eye on.