Former Michigan governor Jennifer Granholm (D) will not run for retiring Democratic Sen. Carl Levin's seat, she announced Friday.

"Friends, thanks for all of the encouragement on the Michigan Senate seat, but I'm not going to run," Granholm wrote on her Facebook page. "I appreciate all of the outreach I've received; for several reasons it's just not right for us (it's a family decision). My best to all the contenders -- Levin's US Senate seat will stay blue!"

Granholm served two terms as Michigan's governor, and was pretty unpopular when she left office in 2011.