There is another side of that coin though, If Rosen continues to improves, and by seasons end, he proves to be a possible franchise QB, when the Draft comes along, Grier will have the choice of staying with Rosen the known commodity, e take a chance on a top college QB that may hopefully look as good or possibly better, then the QB you already know could be a franchise QB in Rosen.
I think Miami needs to be smart, and this may be unfair to Rosen, but even with a leaky O-Line, Rosen will need to not just look good, or show improvement each week, but actually impress the coaching staff to the point he actually takes the offense on his back, and shows week in and week out offensive success, or Miami is drafting in 2020 Rosen's compitition.
He does not have win games, or have huge offensive numbers, because defense could lose games, receivers could drop perfectly placed passes, or players could fumble, and stall drives, but Rosen needs to prove consistency, and play making.