Pedro Feliciano, the former Mets reliever nicknamed “The Perpetual Pedro,” died in his sleep on Sunday night at the age of 45. It is unknown what happened, but Covid-19 has not been mentioned as a cause of death.

According to ESPN reporter Eduardo Perez, the Puerto Rican pitcher was on a jet ski trip with his family, and his passing was very shocking. “He was a really good [baseball player] but a better person off the field,” Perez wrote on Twitter. “He will be missed.”

In his last season right before retirement, Pedro Feliciano told the New York Post that he had a “small hole” in the exterior of his heart. Reporting for training camp in New York, he said that a doctor examined him and told him that it was “not life-threatening.”

“They said they found some little hole in my heart,” Pedro Feliciano said at the time. “I’ve never felt nothing in my heart, so it’s surprising to me.”

It is unknown if his heart condition worsened unchecked over time, or if the exterior hole had anything to do with his passing Sunday night.

“The Mets are so saddened to hear of the loss to their family today,” the New York Mets baseball team wrote in an official statement. “Feliciano will be remembered as a beloved member of the Mets organization for his impact as a great teammate as well as his reputation as one of the most competitive, durable and reliable relievers during his time in Queens.”

“Our thoughts and prayers are with the entire Feliciano family,” the statement concluded. “Rest in peace, Pedro.”

The lefty pitcher debuted for the New York Mets back in 2002 and pitched two scoreless innings in his major league debut. He played for the Mets for nine seasons and pitched a near-franchise record of 484 games. He retired in 2013 due to shoulder injuries, but threw 350 strikeouts with a career average 3.33 ERA over his lengthy tenure in New York.

He was drafted in the 31st round by the Dodgers in 1995 before being traded to New York, where he became a pivotal Mets reliever. He also represented his home country of Puerto Rico in the World Baseball Classic in 2006 and 2009.

Dr. Jose Daniel Quiles, President of The Puerto Rico Baseball Federation, offered his condolences as well, writing that they “deeply regret the death of Pedro Feliciano” and hope he “rests in peace.”

“I was heart broken to hear the news about Pedro Feliciano,” said Mets public relations representative Jay Horwitz. “He was always a team first player. He will be missed. RIP, Petey.”

“Saddened to hear of the passing of former @Mets relief pitcher, Pedro Feliciano,” said the MLB Players Alumni Association. “Gone too soon. Rest in peace, Pedro.”

Many fans on social media shared their tributes to the former Mets reliever, as well, commenting about how Pedro Feliciano was just taking pictures with fans on Sep. 30 at Citi Field, when the Mets hosted the Florida Marlins. The New York Mets beat the Marlins by a staggering 12 to 3 that day.

“He was literally at Citifield posing for pictures a month ago, sad day,” one fan wrote. “RIP Pedro Feliciano. Only 45 years old. Great Met.”

“RIP Pedro Feliciano,” said another fan who shared a picture of him posing with Pedro at a game. “Crazy just saw him.”

Pedro Feliciano is survived by his younger brother Jesus Feliciano, who is also a major league baseball player. After retiring in 2010, Jesus has been a minor league coach for the Tampa Bay Rays.

Feliciano was also married to a woman named Wanda, according to the New York Daily News, and they had two children together: a son, Jakar, and a daughter, Josnelly.

The family has yet to publicly address his passing.