Allegheny County Common Pleas Judge Jeffrey Manning broke a legal norm on Tuesday.

Manning accepted a lenient plea deal offering probation to three of the five white men accused of beating a black man and throwing him onto a Wood Street subway track in Downtown Pittsburgh after a Kenny Chesney concert last May.

But as he accepted those terms, Manning said he was unhappy with the deals reached between the defendants’ attorneys and District Attorney Stephen A. Zappala, Jr.

Manning told reporters he "felt compelled to accept them."

University of Pittsburgh law professor John Burkoff said he understands why an Allegheny County judge might accept a plea deal he doesn’t necessarily agree with.

“Really, judges don’t want to upset the apple cart … because if you actually go to trial, there is some risk that particular defendants might be acquitted,” he said.

Manning declined to comment, but according to state law, judges can reject plea bargains.

Maybe defendants don’t understand their terms or the agreement isn’t voluntary. The victim or police officer might object, or the judge finds there’s no legal basis for the terms, that the punishment doesn’t fit or it's too lenient or too harsh.

In the Wood Street T case, surveillance footage shows five white men – Ryan Kyle, Kenneth Gault, David Depretis and brothers Christopher and Matthew Laplace -- surrounding Kevin Lockett, a black man. Kyle then throws Lockett onto the subway tracks and appears to heckle him. After Lockett climbs up out of the tracks, Kyle is shown beating him repeatedly. The five men then leave with Lockett’s cooler.

Kyle, 22, took a deal Tuesday in exchange for prosecutors' original attempted homicide and robbery charges. He pleaded guilty to aggravated assault, ethnic intimidation, conspiracy to commit robbery and reckless endangerment. Depretis and Gault each agreed to six months' probation and 100 hours of community service. Matthew Laplace took one year of probation and 100 hours of community service.

After the proceedings, Lockett called the probation sentences for Matthew Laplace, Depretis and Gault a “slap on the wrist.”

Assistant District Attorney Julie Capone told the Pittsburgh Tribune-Review she discussed the pleas with Lockett well before the hearings.

Zappala said in a statement Wednesday that the "offers were explained in detail to both the arresting officers and Mr. Lockett, and we are satisfied that the dispositions involving these five defendants are appropriate.”

Burkoff said he thinks Zappala, who is currently campaigning to replace Kathleen Kane as state Attorney General, likely tried to get the best plea deal he could manage from the three defendants sentenced Tuesday.

“You’d have to say it takes some courage for the DA to accept such a deal when he had to know that would be the reaction, but on the other hand, he wanted to do clearly what he thought was right,” Burkoff said.

Zappala said he expects "the most culpable defendant, Ryan Kyle, who was the lone participant in the assault of Mr. Lockett, will face a sentence in the state penitentiary."

Christopher Laplace will be in court Thursday. Kyle will be sentenced in May.

The Associated Press contributed to this report.