Mich. Comp. Laws § 729.212

Sec. 12. Any person so summoned as a juror, who shall fail to attend and to continue in attendance at said trial, unless excused by the judge of the police court, shall be punished by a fine not exceeding $100.00, or imprisonment in the county jail for a period not exceeding 90 days, or by both such fine and imprisonment in the discretion of the court trying the offender.