Messages left for Bell's agent, Herb Rudoy, and Jazz general manager Kevin O'Connor were not immediately returned.
Utah's Al Jefferson and Earl Watson said, to the best of their knowledge, Bell is dealing with a personal matter and nothing abnormal happened after Utah fell to the 76ers.
Jazz coach Tyrone Corbin became confrontational when asked about Bell's absence, declining to officially comment and eventually refusing to answer questions about his player.
"He's not with us. Internal matters, that's all I want to say about it," said Corbin, prior to tipoff against the Bulls.
Corbin hoped Bell would rejoin Utah on Monday for a home game against Detroit. But he wasn't certain, and wouldn't specify a timeline for a resolution to the situation.
Corbin's never understood the criticism ex-Jazz forward Carlos Boozer has received throughout his career.
Boozer spent six successful but injury-plagued seasons with Utah from 2004-10. He entered Saturday averaging 15.4 points and 8.1 rebounds for Chicago, starting all 42 of the Bulls' games. Boozer then scored a game-high 27 points during Chicago's 111-97 victory against the Jazz.
"The guy came into work everyday. He was great with our group of guys," said Corbin, who previously served as an assistant under Jerry Sloan. "He came in early before games to get himself ready to play. He stayed after if his shot wasn't going in. … He's a tremendous player and a great guy."
Corbin said Minnesota shouldn't be counted out of the playoff race just because the Timberwolves lost rookie guard Ricky Rubio (left anterior cruciate ligament) for the season on Saturday.
The Timberwolves are deep and have two capable backup point guards in Luke Ridnour and J.J. Barea. In addition, a young Rick Adelman-coached squad has grown accustomed to winning games and won't easily accept losing.
Minnesota (21-20) entered Saturday ninth in the Western Conference, one game ahead of the Jazz.
"They'll realize with one of the guys out, now everybody has to step up, and what it takes for them to play a certain way to get a chance to win," Corbin said.
Utah rookie center Enes Kanter expressed sympathy for Rubio. They practiced together during the 2011 NBA lockout in Los Angeles and competed in EuroBasket 2011.
"I watched the game [Rubio was injured] and I felt so bad for him because he was playing great," Kanter said.