UPDATE (Dec. 22, 1:30 p.m.) -- The 49ers made it official Saturday, signing linebacker Cam Johnson to a two-year contract and promoting him from the practice squad to the active roster to fill the team's roster vacancy.
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SANTA CLARA -- Rookie Cam Johnson, a seventh-round draft pick who missed most of the 49ers' offseason program after undergoing knee surgery, will be promoted to the 49ers' 53-man roster, coach Jim Harbaugh said Friday afternoon.
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Johnson could be active for the 49ers' game Sunday night against the Seattle Seahawks as veteran backup Clark Haggans is not expected to play due to a shoulder injury. Journeyman Eric Bakhtiari will be the 49ers' top backup at outside linebacker behind starters Aldon Smith and Ahmad Brooks.
Johnson (6-foot-3, 258 pounds) was a seventh-round pick (No. 237 overall) out of Virginia. He was named third-team All-Atlantic Coast Conference after his senior season. He playd 42 games at Virginia with 34 starts. He recorded 12.5 career sacks.
Haggans and 49ers defensive tackle Justin Smith (left elbow) are two players the 49ers originally listed as doubtful for Sunday's game. If Smith is unable to play, second-year nose tackle Ian Williams would be expected to get he call to suit up for the first time this season. Ricky Jean Francois would start, with Will Tukuafu and Williams available as backups.
Last week, the 49ers went more than a week with one vacancy on their 53-man roster after suspending running back Brandon Jacobs for the final three games of the regular season. The 49ers released practice-squad receiver Chad Hall because of an obscure NFL rule that states a team must fill promote a third-year practice squad player to the 53-man roster if they have a vacancy.
San Francisco 49ers
Last week, the 49ers released Hall before the weekend to get around that rule. They re-signed him on Monday. After all, there was no reason to activate a player from the practice squad to the 53-man roster if he is not going to suit up for the game. Such a move would cost the team an unnecessary $17,200 weekly in salary and cap space.