After winning nine of its last 10 to conclude December, Atlanta has a 2-6 mark in 2009 and has dropped five of its last six heading into Monday's game.

A lagging defense can take most of the blame as the Hawks have allowed 100 or more points in six of their last eight games, including Friday's 119-114 loss at Golden State to wrap up a three-game road trip.

They have held the Raptors to less than 100 points in two meetings, but have split those games, winning 110-92 at home on Nov. 7 and falling 93-88 in Toronto on Nov. 28.

Already missing Al Horford, Atlanta could be without starting forward Marvin Williams, who was taken to a hospital Friday after hitting his head on the court when he was fouled in the second quarter. Williams is averaging 13.2 points and a career-best 6.1 rebounds this season.

"Marvin's a big part of what we're doing," Hawks coach Mike Woodson said. "Right now he's still being evaluated for a head injury. We just wish him well and a speedy recovery. We don't even know if he's going to make the trip back, so we'll just have to see."

Horford, the team's leading rebounder at 8.7 per game, has missed the past five games with a bone bruise in his right knee, and is also expected to miss Monday's game.

Toronto, which has lost five straight, has experienced its share of injuries and had only nine players available for Sunday's 117-113 loss to visiting Phoenix.

A strained right hamstring kept starting point guard Jose Calderon out for the eighth time in nine games, and Jason Kapono was scratched due to flu-like symptoms. The statuses for Calderon and Kapono are not known.

Jermaine O'Neal, who returned in Friday's 111-104 loss at Indiana from injury, rested his sore right knee Sunday, but is probable for Monday's game.

With Andrea Bargnani finally playing like a No. 1 draft pick, there are rumors that O'Neal could be traded to Miami soon. Starting in place of O'Neal at center, Bargnani has averaged 21.5 points and 6.5 rebounds. He has also hit 54.5 percent of his 3-point attempts (30-for-55).

Toronto coach Jay Triano tweaked his lineup Sunday, starting Anthony Parker at point guard and Joey Graham at shooting guard. Parker responded with a team-leading 26 points, and Graham scored a career-high 22.

"We played better but it's just so disappointing, time and time again, to come up short at the end," Parker said.