Smith was in uniform but did not play in San Francisco's 23-3 preseason-opening loss to the Baltimore Ravens on Thursday.
Smith could be suspended for multiple violations of the league's personal-conduct substance abuse policies. Last month, Smith was sentenced to three years of probation and to spend 11 days with a work crew after pleading no contest to drunken driving and weapons charges.
Smith will also have to serve 235 hours of community service and pay almost $4,000 in fines as part of his sentence.
Authorities found weapons at Smith's house after a 2012 party in which two people were shot and Smith, 24, was stabbed. He was charged with three felonies.
Last September, Smith smashed his car into a tree and was booked for DUI after his blood-alcohol level was found to be twice the legal limit.
Prosecutors declined to charge Smith after he was arrested at the Los Angeles International Airport in April when police said Smith was acting belligerently, saying that he had a bomb.
- Scooby Axson