Extra points: Like Flacco, cornerback Jimmy Smith has been given a certain amount of latitude on the practice field. But his activity in individual drills and even a few full-team exercises after tearing his left Achilles tendon on Dec. 3 has been an encouraging sign for team officials, who initially thought they would have to open the regular season without Smith. “Jimmy is coming off an Achilles during the season, a tough injury, and did a great job rehabbing it,” Harbaugh said. “He looks pretty darn good out there. We’re still going to take our time, but boy, it’s very good to see — positive development.” … The team announced Saturday its signing of free-agent guard Cameron Lee. Undrafted from Illinois State in 2017, the 6-foot-6, 313-pound Lee spent stints with the New Orleans Saints and Cincinnati Bengals before joining the Chicago Bears’ practice squad Sept. 3. He was promoted to the active roster Dec. 5 and was released May 14. Lee fortifies an offensive line that has practiced without six-time Pro Bowl right guard Marshal Yanda (shoulder – physically-unable-to-perform list), guard Maurquice Shakir (undisclosed) and rookie offensive tackle Greg Senat (unspecified).