Per Jeff Passan of Yahoo Sports, the Pasco County Sheriff's Department confirmed Halladay was killed in a plane crash in the Gulf of Mexico.
Major League Baseball and the Phillies offered their condolences on Twitter after learning of Hallday's death:
Halladay pitched 16 seasons in MLB with the Blue Jays and Phillies. He was a first-round draft pick by Toronto in 1995 and made his MLB debut on Sept. 20, 1998.
In 12 seasons with the Blue Jays, Halladay was named to the American League All-Star team six times and won the 2003 AL Cy Young Award. He was traded to Philadelphia after the 2009 season and won the National League Cy Young Award in his first year with the Phillies.
The Colorado native led all starting pitchers with 58.7 FanGraphs wins above replacement from 2002-11 and ranked fifth with a 2.97 ERA. He became the second pitcher in MLB history with a postseason no-hitter when he shut out the Cincinnati Reds 4-0 in Game 1 of the 2010 NLDS.
Halladay is one of six pitchers in MLB history to win the Cy Young Award in both leagues. He also worked with the Phillies and Blue Jays as a guest instructor during spring training after retiring following the 2013 season.