"Even though it doesn't appear suspicious, it's not unusual that we have an open investigation into someone's death," Barreda said.
Sheriff's deputies were called to a Palm Harbor home at around 10:45 p.m.
Miller was a relief pitcher for the Los Angeles Dodgers, the Toronto Blue Jays, the San Francisco Giants and the Florida Marlins during seven seasons, which ended in 2010, according to Baseball-Reference.com. He won 24 games, lost 14 and saved 33, according to the baseball website.
"He always played baseball, and that was his passion," said his wife, Jessica Miller, of Palm Harbor.
The tattoos that covered his body and his sleeve tattoos that reportedly distracted some batters brought him baseball notoriety. Major League Baseball forced him to wear a long-sleeved shirt underneath his team jersey to cover the sleeve tattoos when he pitched.
Although the rule had been in place, it was dubbed the Justin Miller Rule.
Miller, who was born and raised in California, was drafted by the Colorado Rockies in the 1997 amateur draft. He began his major league career in 2002, and his final appearance with a major league team was in 2010.
Last year, he opened Justin Miller's Legacy Baseball/Softball & Personal Training in Clearwater. He instructed area youths in pitching.
"He was really good at explaining mechanics and motivating kids," Jessica Miller said. "All the kids loved him a lot. It wasn't a place just to learn about baseball but to learn about life."
He was also a volunteer youth baseball coach with the Palm Harbor Little League and a member of its board, Jessica Miller said.
He's survived by his wife; his sons, Joseph, 18, and Johnnie, 7; his parents, Mona and Joe Miller, of Torrance, Calif., and a brother, Corey Miller, of Torrance, Calif.
A memorial service is planned at Sylvan Abbey Memorial Park & Funeral Home in Clearwater. A date hasn't been set, his wife said. A memorial service is also planned in Los Angeles, although a date for that hasn't been set either.