Coach Bill Belichick did not have a timetable for Cassel's return and did not say whether he expected Cassel would play Sunday.
"Right now, we are just taking it day to day," Belichick said. "He's going to take care of what he has to do."
A spokeswoman for the San Bernardino County Sheriff-Coro ner's Department said the preliminary findings indicate Mr. Cassel, a former Hollywood script writer, died in his home of natural causes.
"At this point, we don't see any signs of trauma," Sandy Fadland said. "It appears to be a natural death."
She said the coroner will conduct more extensive tests before declaring the official cause. Greg Cassel had been recovering from major reconstructive shoulder surgery after being thrown by a horse he was training, but he otherwise appeared in good health in September during an interview with the Globe.
Funeral services for Cassel's father are scheduled for Monday in Granada Hills.
Belichick, whose father, Steve, died the night before a win over New Orleans in 2005, sympathized with his quarterback's loss.
"It's bigger than football," said Belichick. "I've been through that during the season as well, a personal situation you just have to deal with. Like I said, our thoughts and prayers are with him."
Cassel's teammates expressed similar sentiments of support and sorrow. "Matt is more than just a teammate to me," said running back Sammy Morris. "His loss is our loss."
Defensive end Richard Seymour, whose father, Richard Sr., took his own life as part of a murder-suicide in April 2004, said Cassel should be given as much time as he needs to grieve and that whether he decides to play against Oakland or not, the team is behind him.
"It's definitely a tough situation," said Seymour, who indicated he offered his condolences to Cassel yesterday during breakfast at the team hotel. "Some guys have done it and some haven't. It's a personal issue, and it's a personal choice. Whatever he chooses to do, we support him 100 percent. That's a [decision] that him and his family would have to make, but whatever he decides to do, we support him 100 percent."
If Cassel does not play, rookie Kevin O'Connell, a third-round pick out of San Diego State, would get the call.
