League sources told ESPN and the Chicago Sun-Times that Smith spent Tuesday working out at Halas Hall, but he will be out indefinitely while the team gives him time to deal with a personal matter. According to ESPN, Smith hadn't been acting like himself around the team facilities for the last week or so.
"It's completely a personal issue," Nagy said. "I'm not going to answer any more about it. That's where it's at right now. I understand where you all are coming from, but out of respect to this right now, I just want to leave it at that."
Smith, who wasn't listed on the team's official injury report last week, was a surprise inactive for Chicago's matchup against the Vikings on Sunday. He was downgraded to doubtful about 20 minutes before the list of inactives came out.
"Again, he's completely a personal issue," Nagy said Monday. "For us, it's something that we're going to leave it at that right now."
Smith, the No. 8 overall pick in the 2018 NFL Draft, recorded a team-high 121 total tackles in 16 regular-season games (15 starts) for the Bears last season. He was credited with six combined tackles in the Bears' win over the Washington Redskins in Week 3.