It's has been expected, and now it is official.
In an e-mail to supporters today, this logo was at the top:
So,as the logo indicates, he's running for the U.S. Senate.
From his e-mail to supporters:
Following Carl’s decision, I have been humbled by the voices from every corner of Michigan who have enthusiastically encouraged me to run for the U.S. Senate. It is a decision that can only be made as a family and over the past few weeks, my wife Colleen and I, along with our three wonderful children, have discussed it at length. We wanted you to be among the first to know of our decision. Today — I am officially announcing that I am a candidate for the U.S. Senate in 2014.
He'll be speaking with the press today in Rochester at 2:15 p.m.
Michigan Radio's Steve Carmody will be there and will bring us an update.