"I feel good," said Speights, who "felt a pop" in his right calf in Game 3 of the Western Conference semifinals. "I just haven't put a uniform on yet."
On Tuesday, Warriors coach Steve Kerr announced that Speights had been cleared to return to game action.
When asked if he's fully healthy, Speights replied: "Ain't nobody 100 percent at this time, but it's better."
Speights averaged 10.4 points and 4.3 rebounds in 15.9 minutes per game in the regular season, but his production was down to 4 points and 2.3 rebounds in 7.3 minutes per game in seven playoff games.
Golden State hosts the Cleveland Cavaliers in Game 1 of the NBA Finals at 9 p.m. ET on Thursday.