AUBURN — A Leeds man imprisoned on kidnapping and robbery convictions last year pleaded guilty Monday to aggravated assault in connection with a hit-and-run last summer.

He won’t spend any additional time in prison if he stays out of trouble during his probation.

Donald White, 30, of 113 Anson Road pleaded guilty to three of five felony counts from an Androscoggin County grand jury indictment. He agreed to a sentence of six years in prison on the assault charge, with all six years suspended. That was followed by five years in prison for guilty pleas to leaving the scene and theft by extortion. That sentence, also suspended, would be served at the same time as the six years if he were sent to prison on the assault charge.

White also was sentenced to three years on probation for the assault charge and two years on probation for the other two recent charges, to be served at the same time as the three years.

He is serving at Maine State Prison a four-year sentence on the kidnapping and robbery convictions stemming from his role in an incident involving an acquaintance who visited White to buy a used car. The man was beaten and locked in a car trunk and driven to his girlfriend’s home, where he was robbed.

White pleaded guilty to the charges in November shortly after his trial had gotten under way. When he is released from prison, he must serve three years on probation for those crimes.

A jury was scheduled to be picked Monday in his latest trial, but he entered guilty pleas instead.

That case involved a hit-and-run in September that sent a Turner man to the hospital in critical condition.

Police said White and 31-year-old Jason Gagnon wrestled over his girlfriend at a Leeds home.

White returned to the driver’s seat of a full-size pickup truck when Gagnon started screaming at his girlfriend who was in the passenger side of the truck. Words were exchanged between Gagnon and White. As Gagnon walked in front of the truck, police said, White put the truck in gear and began to accelerate, running over Gagnon.

After backing up the truck, White got out and went to Gagnon, who was lying on the ground. Police said Gagnon didn’t want to be touched and said he was going to walk home. His girlfriend insisted they needed to call for help.

White fled the scene before medical crews arrived, police said.

Gagnon’s injuries were consistent with having been struck by a heavy object, enough to crush his sternum into his backbone, causing damage to organs, including his heart and lungs, according to medical reports.

Police said they found tire tracks at the scene that matched the treads of tires on the truck White was driving that night that was owned by a Greene man.

The theft by extortion charge was unrelated.