BOSTON — Red Sox slugger David Ortiz, Boston’s beloved “Big Papi” who helped the cursed franchise end its dynasty of disappointment and cursed out the bombers who attacked his adopted city, said on Wednesday he will play one more year before retiring.

On the day that he turned 40, the Dominican designated hitter said in a video posted on The Players’ Tribune (http://bit.ly/1WYZJxo ) that the 2016 season will be his last. The post was titled “40.”

“Life is based on different chapters, and I think I am ready to experience the next one in my life,” he told his fans. “I wish I could play another 40 years, so I could have you guys behind me, but it doesn’t work that way. After this year, time is up. So let’s enjoy the season.”

Ortiz led the Red Sox to three World Series championships, hitting 503 homers in a career of clutch at-bats while serving as the inspiration that turned a tormented franchise into a big-market bully.

Already treasured for his big hits and even bigger personality, Ortiz further cemented himself in the city’s lore after the 2013 Boston Marathon bombings that killed three people and injured hundreds more. Taking the microphone before the ballclub’s first game back, Ortiz told a Fenway crowd that included the governor and top police officials: “This is our (expletive) city. And nobody’s going to dictate our freedom.”

With “Boston Strong” as its rallying cry, the Red Sox returned to the World Series. Ortiz batted .688 in the six-game victory over the St. Louis Cardinals, and was named the Series MVP. He is one of just four players in baseball history with at least 500 career homers and three World Series championships, joining Hall of Famers Babe Ruth, Mickey Mantle, and Reggie Jackson.

“He’s given all of our fans so much reason to cheer,” Patriots quarterback Tom Brady said on Wednesday. “I’ve got a lot of respect for him and the way that he’s always, I think, brought a great leadership to his team.”