Mallett did not fit into RR program or plans, there was absolutely no incouragement to keep him, and the guys who went to the NFL did so largely because of RR.
Directly from Mallett's own webpage: "As soon as Lloyd Carr retired and Rich Rodriguez was hired, Mallett's days seemed to be numbered because of Rodriguez's spread offense that has featured mobile quarterbacks.", call it what you want there was NO desire on RR part to keep Mallett.
Justin Boren's own press release: At the time of his statements he drew a lot of ridicule, however as time went on his concerns proved to be valid! And keep in mind that Justin Boren and his family were Michigan Men, as his father was a linebacker and captain at Michigan.
“I regret leaving behind my friends and teammates, but I need to stand up for what I know is right,” Boren said in a statement released Wednesday afternoon. “I wore the winged helmet with pride, whether we won or lost, whether things were going well or times were tough.
“Michigan football was a family, built on mutual respect and support for each other from (former) Coach (Lloyd) Carr on down. We knew it took the entire family, a team effort, and we all worked together. I have great trouble accepting that those family values have eroded in just a few months. That same helmet, that I was raised on and proudly claimed for the last two years, now brings a completely different emotion to me, one that interferes with practicing and playing my best and mentally preparing for what is required.
“That I am unable to perform under these circumstances at the level I expect of myself, and my teammates and Michigan fans deserve, is why I have made the decision to leave. To those of you outside the program, the loyal Michigan fans and alumni, I know you will have trouble understanding, but I do want to thank you for your years of support. I wish my teammates the best and will always be proud to have been a part of Michigan football over the past two years.”