Fredette returned to the NBA last season, appearing in six games for the Phoenix Suns. Before that, he spent five seasons in the league across four teams.
Fredette played 65 total minutes for the Suns, scoring 22 points and shooting 8-of-29 from the field.
He joined the Golden State Warriors for the 2019 NBA Summer League but left abruptly ahead of Golden State's third game in the California Classic.
"I spoke with him last night," Warriors summer league coach Aaron Miles told reporters. "He said he wasn't ... was kind of over it. I guess his agent has spoken with our people, so I called him and thanked him for his time. His reasoning is his reasoning. I'm glad he had a chance to come and impact us."
The Bay Area News Group's Mark Medina reported Fredette stepped away in order to avoid injury after receiving interest from teams overseas.
The 10th overall pick in the 2011 draft, Fredette struggled with the adjustment to the NBA early in his career in large part because his prodigious scoring in college didn't translate to the next level.
He left the NBA following the 2015-16 season and signed with the Shanghai Sharks of the Chinese Basketball Association. During a Sharks loss last November, he scored 75 points and had a 73-point scoring game during the 2016-17 season.
Fredette will turn 31 in February. By leaving the Warriors and moving to Greece, he likely closed the door on another NBA comeback.