Oakland A's Minor League right-hander Sean Murphy died on Monday in Arizona at the age of 27.
The Athletics confirmed the death on Tuesday, calling his passing a "tragic loss." The cause of death remains unknown.
"The A's are deeply saddened by the tragic loss of Sean Murphy," said A's vice president Billy Beane. "Our thoughts and prayers are with his family and friends."
Murphy was a 33rd-round pick by the A's in the 2010 Draft out of Keystone College and went 32-32 with a 4.26 ERA in 105 career Minor League games, reaching Triple-A in 2014. He struck out 462 batters, walked 167 and owned a 1.33 WHIP in 490 2/3 career innings from 2010-14 in the Oakland system.
The Philadelphia native's best season came in 2012, when he set career highs with 11 wins and 159 strikeouts in 27 starts. He owned a 3.91 ERA that summer between Class A Burlington and Class A Advanced Stockton, earning a pair of league Pitcher of the Week honors in April and June. Murphy ranked second among A's Minor Leaguers in innings pitched in 2012, tied for second in wins, was third in strikeouts and ninth in ERA.
Murphy hadn't pitched since Aug. 5, 2014, a season in which he appeared at Double-A Midland and Triple-A Sacramento, going 6-8 with a 4.89 ERA in 20 starts. He spent the 2015 season on the 60-day disabled list following Tommy John surgery and was suspended for 50 games by Major League Baseball on Feb. 4 for an undisclosed drug of abuse.
Former teammates expressed their condolences Tuesday on Twitter.
"Sad to hear about the passing of an old teammate in Sean Murphy," wrote Indians outfielder Michael Choice, who was also drafted by Oakland in 2010. "It was a pleasure knowing you. Rest In Peace Murph."
"Sad to hear about the passing of Sean Murphy," tweeted Cardinals righty Deck McGuire. "Only knew him for a bit, but his optimism and attitude was contagious!"
Former A's lefty Jeff Urlaub, who also played at Midland and Sacramento in 2014, said Murphy was among his best friends in the Oakland system.
"RIP Sean Murphy," he tweeted. "One of my best friends in the A's organization. Unreal teammate but even better guy. I'll miss you brotha!"
Murphy is the fourth Minor Leaguer to pass away this year. Yankees infielder Sandy Acevedo, 18, died on April 24 in a car accident in the Dominican Republic after Astros right-hander Jose Rosario lost his life in a motorcycle crash on Jan. 24. Orioles infielder Ramon Ramirez was killed in a motorcycle wreck on Jan. 31 and another Oakland prospect, Mike Nolan, was killed last year in a shooting in New York -- he died in October.