Smith was diagnosed with a low left ankle sprain following Sunday's practice, Mike Reiss of ESPN.com reports.
During a 1-on-1 drill, Smith got tangled up with a defensive back, had an awkward landing and limped to the sideline. After an examination of his left foot, he could miss some practice in the short term, but the injury isn't deemed to be a serious one. Elsewhere in the tight end room, Hunter Henry returned to practice Sunday after missing the past week due to a shoulder issue.