Marrero's grandson said he died in the early afternoon.
"He woke up in the morning and it was like he wasn't there. He wasn't reacting," Rogelio Marrero told The Associated Press.
"Connie" Marrero, as he was known in the States, was renowned for his control and for his presence on the mound despite standing just 5 feet 5 inches tall and weighing 158 pounds.
What Marrero lacked in heat he made up for with a tricky repertoire of breaking balls, knucklers and other off-speed pitches. He also had a quirky windup that Felipe Alou once likened to "a cross between a windmill gone berserk and a mallard duck trying to fly backwards."
In interviews with the AP in recent years, Marrero recounted the highlights of a career facing off against Hall of Famers such as Mickey Mantle and Larry Doby. Beating the New York Yankees was especially gratifying, he said. He also recalled struggling against left-handed batters in general, and southpaw slugger Ted Williams in particular, a frustration shared by plenty of his contemporaries.
"One day Williams got two home runs off me, and afterward he came up to me and said, 'Sorry, it was my day today,'" Marrero said in 2012. "I responded, 'Ted, every day is your day.' "
Born April 25, 1911, in the town of Sagua la Grande, about 220 miles (350 kilometers) east of Havana, Marrero's nickname on the island was "The Peasant from Laberinto," after the farm where he grew up.
He began his career playing third base, shortstop and in the outfield, and his debut on the mound came by accident one day in 1935 when his Sagua club didn't have a regular pitcher available. Marrero won the game, and the team asked him to remain at the position.
He went on to play at Cienfuegos, Almendares, Marianao and Havana, and briefly in the Mexican league in 1945 for the Indios of Juarez. He also starred on Cuba's national team.
Marrero was already near the end of his career when he made his U.S. debut in 1950 at the age of 39. In five seasons with the Senators, he compiled a 39-40 record with an ERA of 3.96 and 297 strikeouts. He was named an All-Star in 1951.
Cut by the Senators in 1955, he returned to Cuba to play for the Havana Sugar Kings and retired after his final season in 1957. He continued to work as a coach and instructor into his 80s, and was honored by the government as a Hero of the Republic of Cuba in 1999.
Past the century mark, Marrero was blind, hard of hearing and confined to a wheelchair. He spent much of his time listening to Cuban baseball games on the radio, often chewing on a cigar. He had difficulty speaking, but visibly lit up when reminiscing about his time in the Major Leagues.
"Putting on that uniform always made me feel bigger, more powerful," Marrero said in 2013, on his 102nd birthday.
Marrero became the oldest living ex-Major Leaguer in February 2011 after the death of former Brooklyn Dodgers infielder Tony Malinosky.
Baseball Hall of Fame librarian Jim Gates said that distinction now goes to Mike Sandlock, a 98-year-old former catcher who played 195 games with the Braves, Dodgers and Pirates. Sandlock was born Oct. 17, 1915.
In recent years, Marrero received $30,000 from Major League Baseball under a payout program for players who were active between 1947 and 1979. The funds had been delayed for two years by complications related to the U.S. economic and financial embargo on Cuba.
Rogelio Marrero said his grandfather's remains will be cremated and the family hopes to have his ashes rest in a pantheon for Cuban ballplayers.