"He's gotten a little bit better, but nothing significant," Skiles said. "Sometimes these things seem like they're never going to end and then someone wakes up in the morning and it's gone."
Skiles said doctors have told him there's nothing structurally wrong with Bogut's back but couldn't give a timetable when the center might return. Bogut was hurt against Houston on Dec. 31 after a hard charge, but managed to stay in the game.
"He took a pretty significant blow and that's what flared it up," Skiles said. "He's leading our team in taking charges and several times he's taken some pretty good hits this year. I think the Houston game it really flared up on him and it didn't go away. In the past, it's gone away the next day. We've got to get it to go away."
The Bucks are 1-4 this season without Bogut, winning for the first time against Toronto on Monday night. Milwaukee is 4-21 overall without the 7-foot center after drafting him No. 1 overall in 2005.
Dan Gadzuric replaced Bogut in the lineup.
Bogut, averaging 11.5 points and 10.5 rebounds, signed a five-year contract extension this summer worth a guaranteed $60 million.
He played in every game in his rookie season and only missed the final 16 games of the 2006-07 season with a foot sprain. Last season, he missed four games due to injuries.
"He's doing everything he can do. He's getting constant treatment," Skiles said. "One of these days he'll say he's ready to go and we'll get him back out here."