James missed the club's final home exhibition game against the Washington Wizards on Wednesday night because of flu-like symptoms that have been bothering him for several days. Forward Darnell Jackson and guard Coby Karl were also out with the flu.
James and his two teammates were told to stay home so they don't spread the flu.
As a standard precaution, all of the players will be tested for the H1N1 virus, team officials said.
The NBA's reigning MVP, James has been under the weather for the past few days. He was sent home from practice on Tuesday and was not at the Wednesday morning shootaround.
West returned to practice this week with the Cavs, who allowed him to leave the team to attend to medical and personal issues. West has been treated for bipolar disorder, and last month he was arrested near his home in Maryland on misdemeanor weapons possession charges.
During media day, West indicated he had stopped taking his medications this summer.
The Cavaliers gave West the option of working out at Quicken Loans Arena or staying at the team's training facility in Independence. He chose to stay at Cleveland Clinic Courts.
Coach Mike Brown said there is no timetable for West to make his preseason debut.
"I'm literally taking it one day at a time," Brown said. "I haven't thought much about it except to make sure he is OK."