Smith took just 12 snaps in his first game back after missing five contests while receiving substance-abuse treatment.
This week, the Saints will throw the ball -- often.
Fangio declined to say whether or not Smith will start. Dan Skuta, who replaced Smith in the starting lineup, will play despite a foot injury. Skuta and rookie Corey Lemonier have stood in well for Smith, but neither of them bring the same type of production.
Smith provides the 49ers with the best chance to disrupt passing plays by getting Brees off his spot. Smith was disappointed he didn't get a full slate of reps last week, but he should see the field plenty Sunday as the 49ers claw for playoff position.