Leo López said that the retired athlete's liver was also damaged and that he was in stable condition in intensive care. He said Ortiz will be flown to Boston once his condition improves.
Ortiz, 43, is one of the most popular figures in sports history in the Dominican Republic and Boston, a fearsome power hitter with a ready smile. He led the Red Sox to three World Series championships, was a 10-time All-Star and hit 541 home runs.
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Dozens of fans crowded the hospital in Santo Domingo where Ortiz was being treated, causing a traffic jam. In the U.S., fans prayed for his recovery.
"He's a great friend to the city of Boston," Sheila Kieran said. New England Patriots star Julian Edelman joined the throngs of pro sports figures who took to social media to wish Ortiz well, assuring him on Instagram: "Papi, all of New England has your back."
Ortiz was at the Dial Bar and Lounge in Santo Domingo on Sunday night when a gunman approached from behind and shot him at close range, said National Police Director Ney Aldrin Bautista Almonte.
The gunman was captured and beaten by a crowd of people at the bar, and police were waiting for him to undergo treatment for his injuries before questioning him, authorities said. Investigators said they were trying to determine whether Ortiz was the intended target.
Ortiz's father, Leo, told reporters he had no idea why someone would have shot at his son.
"He is resting," the elder Ortiz said. "Big Papi will be around for a long time."
The Red Sox said in a statement that Ortiz was wounded in the "lower back/abdominal region" and that the team offered his family "all available resources to aid in his recovery."
Two other people were wounded, including Jhoel López, a Dominican TV host who was with Ortiz. Police believe López was wounded by the same bullet, Bautista said.
López was shot in the leg, and his injuries were not life-threatening, said his wife, Liza Blanco, who is also a TV host.
Police did not identify the third person or detail that person's injuries.
The bar is on Venezuela Avenue, a bustling nightlife district packed with dance clubs and expensive bars that Ortiz is known to frequent.
Ortiz, who retired after the 2016 season and lives at least part of the year in the Dominican Republic, is often seen getting his cars washed and hanging out with friends, including other baseball players, artists and entertainers.
The Red Sox retired his number, 34, in 2017, and Boston renamed a bridge and a stretch of road outside Fenway Park in his honor. He maintains a home in Weston, on the outskirts of Boston.
Ortiz galvanized the city after the 2013 Boston Marathon bombing that left three people dead, bellowing through a megaphone at Fenway Park: "This is our (expletive) city!"