A Butler man responsible for the fractured skull of his girlfriend's 9-month-old daughter could spend as little as 30 days in jail.

Court records say Matthew Gene Blumling, 24, was watching the baby, Karmin, when the injury occurred Jan. 9.

Investigators were alerted by hospital officials, who treated also Karmin for a broken leg and arm.

Blumling was charged with multiple crimes, including a felony count of aggravated assault. But in June he pleaded guilty to misdemeanor counts of child endangerment and simple assault.

Butler County Assistant District Attorney Richard Bosco explained the circumstances of the plea offer.

He said officials could not prove exactly where, when or who the baby was with when any of the injuries occurred —- short of the head injury that definitely occurred the evening in question while the child was in Blumling's care.

Bosco said the plea offer was grounded in what prosecutors believed they could prove in court.

Butler County Judge Timothy McCune sentenced Blumling to the terms of his plea arrangement: 3 to 12 months in county prison and two years' probation.

Blumling could be paroled to house arrest with electronic monitoring after serving 30 days if he is well behaved behind bars.