The 49ers finalized a contract with free agent outside linebacker Clark Haggans on Sunday after he passed a team physical, a source told CSNBayArea.com.
Because the deal took place after the close of the NFL business day, the 49ers did not announce the transaction and they are not required to make a corresponding move to clear a roster spot until Monday.
However, the 49ers might not have Haggans' services at the beginning of the season. He faces league discipline after serving jail time in June after pleading guilty to extreme DUI stemming from an April 2011 incident. Haggans' hearing in front of the NFL is scheduled for Wednesday.
Haggans, 35, started all 16 games at left outside linebacker for the Arizona Cardinals last season. The 49ers kept three outside linebackers -- Aldon Smith, Ahmad Brooks and Parys Haralson -- on Friday as part of their cuts to 53 players.
He spent the past four seasons with Arizona, where he played in 56 games (43 starts) and collected 14 sacks. He played nearly 75 percent of the Cardinals' defensive snaps last season and also contributed on special teams.
Haggans played his first eight NFL seasons with the Pittsburgh Steelers. His best season was in 2005, when he recorded nine sacks.