49ers notes: Team adds Asa Jackson to cornerback corps

The 49ers added their fourth Sacramento-area native to the roster Tuesday, signing cornerback Asa Jackson to a one-year deal.

Jackson, 27, originally was drafted by the Baltimore Ravens in the fifth round in 2012. Playing for the Ravens and Lions, he has appeared in 22 games with 34 tackles and four passes defensed. Jackson played in high school at Christian Brothers, which is where third-round draft pick Ahkello Witherspoon also went to school.

Defensive end Arik Armstead and tight end Cole Hikutini also are from the Sacramento region. Receiver DeAndre Carter played at Sacramento State. The 49ers have had a number of injuries at cornerback, including to rookies Zach Franklin and Adrian…