Mich. Comp. Laws § 168.58: Gubernatorial candidates; withdrawal after nomination.

Sec. 58.

When a candidate of any political party for the office of governor has filed a nominating petition for such office and has been nominated for said office by said party, he shall not be permitted to withdraw unless he has removed from the state, or has become physically unfit. This prohibition shall not be construed to prohibit the withdrawal of any candidate who has been nominated without having filed a nominating petition and whose name has been written or placed on the ballot of any political party.