Dooley said Brown told him Thursday that he was dealing with family and personal problems that included "some of the reasons why he came here." Brown was not present for practice.
"I was a little surprised, but you can only control what you can control," Dooley said. "He went through the entire offseason, but I also think that this wasn't something from the last three weeks. But I'm not here to recruit. I'm here to coach."
The Wichita, Kan., native averaged 38.3 yards in 12 games as a freshman in 2009.
Brown was rated as one of the top recruits in the nation in 2009, and his recruitment process drew a lot of attention thanks to his relationship with adviser Brian Butler.
The NCAA investigated whether money was improperly raised for Brown to visit colleges while in high school. Neither Brown nor Tennessee, who was not recruiting him at the time, were punished.
Brown originally committed to Miami, where his brother, Arthur Brown Jr., played but instead signed at Tennessee after Lane Kiffin was hired as coach.
In January, Kiffin left Tennessee to coach at Southern California and Arthur Brown left Miami and enrolled at Kansas State earlier this month.
Dooley says Brown will remain enrolled at Tennessee for the rest of the spring semester but did not indicate if he would then transfer.
"We want Bryce here. He's going to be here through the rest of the semester, but my focus really is on the 85 guys who are here and have great spirit about the direction of the program and are excited about having our first practice," Dooley said.
Fellow running back David Oku said Brown's decision caught his teammates somewhat by surprise.
"Everybody makes their own decisions. All we can do is hope he doesn't (leave), but we can't control what somebody else does," Oku said. "You know how coach Dooley said, everybody's got to worry about taking care of themselves to get the team chemistry going."