NFL.com's Ian Rapoport reported that the veteran right tackle wasn't on hand for practice, but a source indicated that Smith's absence isn't football- or contract-related.
The team plans to address Smith's status after Tuesday's session. The four-year veteran has been in constant contact with Bengals officials, who are fully aware of his personal situation, according to Rapoport. Smith is expected to report later this week or, at latest, by early next week.
Smith also missed the entirety of the team's organized team activities and could, in theory, be fined for missing minicamp.
When he's present, Smith -- drafted sixth overall by the Bengals in 2009 -- is a sturdy right-side protector who graded out as football's fifth-best tackle last season by ProFootballFocus. Even with Smith entrenched, quarterback Andy Dalton was sacked 45 times, third most in the NFL, so the Bengals hardly can afford to have their best blocker stay away for long.
"Andre won't be here for the three days," Lewis said, adding that Smith is subject to being fined for his absence. "He is dealing with something he has to get through. We hoped he'd be here, but he has some personal things he's dealing with."
Follow Marc Sessler on Twitter @MarcSesslerNFL.