DETROIT — A recreational soccer player who delivered one punch to a referee that killed the man pleaded guilty to involuntary manslaughter Friday in a deal with prosecutors that calls for him to serve up to 15 years in prison.

Bassel Saad, 36, acknowledged in a Detroit courtroom that he struck John Bieniewicz during a game last summer at a park. Bieniewicz died two days later. Saad initially was charged with second-degree murder and had been scheduled to stand trial beginning Monday.

The auto mechanic from Dearborn will be sentenced March 13. Under the plea deal, he could be sentenced from eight to 15 years in prison. He would have faced up to life in prison if convicted as charged. Because Saad is not a U.S. citizen, he also could be deported.

Kris Bieniewicz, the referee’s wife, attended Friday’s hearing, but did not speak to reporters.

Bieniewicz, a medical assistant at a children’s hospital whose wife described him as “just an easygoing guy,” was killed while refereeing an over-30 men’s league match at Mies Park.

Bieniewicz, 44, left behind his wife and two sons.

Kris Bieniewicz recently testified in support of proposed legislation that would make it a felony to assault a sports official.