What I would do and what Brown would do with regards to Keon is very different. I would be starting Keon, at 28+ MPG. Monk would fill in at the back-up 1/2, Huerter the 2/3, Lyles and IJ take the back-up 4/5.
With what Brown is doing with the rotation, there's not much more room than the current 15-20 MPG role he's currently in. The most realistic thing he could probably do is shave off a few minutes from every one of the starters, who are among the league leaders in MPG and that lets you get more Keon on the floor. But Brown seems insistent on keeping the rotation very tight and running the starters those huge minutes. Probably something with what they see on film, in practice, etc, but that's been their philosophy this season.