ENGLEWOOD, Colo. -- Raiders Head Coach Dennis Allen, who spent the 2011 season as the Broncos' defensive coordinator, left the team after its 20-17 loss to the Cleveland Browns to be with his ailing father.

Monday night, Allen's father, Grady, passed away at the age of 66.

"I just want to pass on our condolences to Dennis Allen and his family on the passing of his father, Grady," Head Coach John Fox said to open his press conference Tuesday. "Dennis was a good friend, was on the staff here a year ago. Most everybody here got a chance to meet his dad and so our well wishes and thoughts and prayers are with the Allen family."

In Allen's absence, Raiders Offensive Coordinator Greg Knapp and Defensive Coordinator Jason Tarver split the head coach's duties. Allen is expected to return to Oakland Wednesday evening and coach the team against the Broncos on Thursday.

Raiders defensive back Michael Huff said the team first heard the news Tuesday morning.

"When we first heard it, we were shocked -- we knew he was sick, but we didn't know to what extreme," Huff said on a conference call. "Coach Allen's a part of our family, so his dad's a part of our family. Anytime a part of our family dies, it's a sad moment. We know we have to go ahead and mourn but still go out there and play well."

Fox said the Broncos organization will "be involved" when any services for Allen's father are announced. He said he sent a text to Allen expressing his condolences.

Cornerback Champ Bailey said he will most likely wait until he sees Allen on Thursday to share his sympathy.

"We're aware of that and he's in our prayers," Bailey said. "That's all we can do for him from here but I hope he can get through this and make it back on the field because that's where he belongs."