NOBLESVILLE, Ind. — The NFL suspended Indianapolis Colts owner Jim Irsay for the first six games of the season Tuesday and fined him $500,000 for violating its personal conduct policy, coming down hard just hours after he pleaded guilty to a misdemeanor stemming from a March traffic stop.

Commissioner Roger Goodell said Irsay is barred from team facilities, practices and games and cannot represent the Colts and NFL meetings or events. The fine levied Tuesday is the maximum allowed under league rules.

“I have stated on numerous occasions that owners, management personnel and coaches must be held to a higher standard than players,” Goodell told Irsay in a letter released publicly by the NFL. “We discussed this during our meeting and you expressed your support for that view, volunteering that owners should be held to the highest standard.”

Irsay pleaded guilty Tuesday morning to a misdemeanor count of driving while intoxicated. Irsay, 55, admitted to a Hamilton County judge that he was under the influence of the painkillers oxycodone and hydrocodone when he was arrested March 16 near his home in the Indianapolis suburb of Carmel.

Irsay will be on probation for a year and is prohibited from drinking or possessing alcohol during that time. His driver’s license also was suspended for one year.

The Irsay case was closely watched around the NFL — not least among players — because there are few examples of the league punishing an owner. Detroit Lions President Tom Lewand was suspended for 30 days and fined $100,000 in 2010 for violating the NFL’s personal conduct policy following his guilty plea to driving while impaired.

A player with a first-offense misdemeanor DUI would not be suspended and would be fined no more than $50,000 under terms of the collective bargaining agreement with the NFL Players Association.