(CNN) -- Cleveland Browns wide receiver Donte Stallworth has been suspended indefinitely by the National Football League, days after he pleaded guilty to killing a pedestrian while driving under the influence of alcohol, the NFL said.
Cleveland Browns wide receiver Donte Stallworth on Tuesday pleaded guilty to DUI manslaughter.
Stallworth, 28, pleaded guilty in a Florida court Tuesday to DUI manslaughter charges in the March death of construction worker Mario Reyes. Under terms of a plea agreement, he will serve 30 days. Prosecutors said he began serving his sentence immediately.
"The conduct reflected in your guilty plea resulted in the tragic loss of life and was inexcusable," NFL Commissioner Roger Goodell told Stallworth in a letter Thursday, the league said. Excerpts from the letter were posted on the NFL Web site.
"While the criminal justice system has determined the legal consequences of this incident, it is my responsibility as NFL commissioner to determine appropriate league discipline for your actions, which have caused irreparable harm to the victim and his family, your club, your fellow players and the NFL."
Stallworth's suspension is effective immediately, the league said. Goodell wrote in the letter that "in due course" the league would contact his attorney to schedule a meeting with him, after which a final determination would be made on discipline.
Stallworth was driving his black Bentley GT east on the MacArthur Causeway, which connects Miami, Florida, to the South Beach area of Miami Beach, when he struck Reyes on the morning of March 14, according to prosecutors. He had been drinking at a Miami Beach club, according to court documents. His blood alcohol level was 0.126 percent, prosecutors said; Florida's legal limit is 0.08.
Reyes, 59, reportedly was heading to a bus stop after work when he was struck. Court documents said he suffered "critical head, chest and abdominal injuries" and died at a hospital.
When police arrived at the scene, Stallworth told them he was the driver of the car and admitted striking Reyes.
During Tuesday's hearing, Stallworth offered his "deepest condolences to the Reyes family."
"Though I cannot bring back Mr. Reyes or ease his family's pain, I can and will honor his memory by committing my time, my resources and my voice by educating this community about the dangers of drunk driving," he said.
Stallworth could have served up to 15 years in prison. But State Attorney Katherine Fernandez Rundle noted in a statement that he cooperated with authorities and had no previous criminal record or traffic violations. Reyes' family supported the plea agreement, she said.
Stallworth's attorney, Chris Lyons, on Tuesday told CNN sister network HLN that Stallworth had reached an "amicable" financial settlement with Reyes' family but would not disclose the amount. He said the length of Stallworth's jail term "had nothing to do with Donte Stallworth being a celebrity, a professional football player or money."
Stallworth has shown "genuine remorse" and accepted responsibility for his actions, Lyons said.
Goodell wrote Stallworth that there is "ample evidence to warrant significant discipline" under both the NFL's personal conduct and substance abuse policies. "There is no reasonable dispute that your continued eligibility for participation at this time would undermine the integrity of and public confidence in the league," the letter said.
"Everyone associated with the league derives tremendous benefits from participating in our game and from the extraordinary support we receive from the public," Goodell wrote. "With these benefits comes, among other things, the responsibility to conduct ourselves in a lawful and responsible way, with no entitlement to or expectation of favorable treatment."
Goodell notified NFL clubs earlier this year that there would be increased emphasis on addressing driving under the influence and other misconduct, the league said. It noted the NFL offers a "safe rides" program used by most clubs to provide players and other employees with alternative transportation if they have been drinking.
Under terms of Stallworth's plea agreement, he will face two years of house arrest upon his release. He is also required to donate $2,500 to Mothers Against Drunk Driving, serve eight years of probation and submit to random drug and alcohol testing throughout his probation. His driver's license was permanently revoked.
CNN's Rich Phillips contributed to this report.