OWINGS MILLS, Md. -- Wide receiver Chuck Jacobs, a dark horse contender to make the 49ers' roster, tore the anterior cruciate ligament in his right knee Thursday night and will be out for the season, coach Jim Harbaugh announced between Saturday's joint practices at the Baltimore Ravens' facility.
"That hurt me. That was my guy," cornerback Chris Culliver said. "That was my guy who worked out with me in the offseason, that was my guy who kind of stuck around and understood the process I was going through."
Culliver spent the offseason recovering from his own torn ACL, sustained in last summer's training camp. A year later, Culliver started at right cornerback in the exhibition opener.
"Like I told you before, it's so easy to do, and you've seen it a couple times, now," said Culliver, alluding to the ACL tear Kendall Hunter sustained two weeks ago in practice.
"It's so easy to do but so hard to come back. I'm going to be definitely by his corner, talking to him and keeping his head up and spirits high."
In a corresponding roster move, the 49ers signed wide receiver Lance Lewis, who spent last season with Washington, mostly on the practice squad.
Jacobs said after Thursday's exhibition loss that he thought he merely hyperextended right knee on a kickoff return, as he fell out of bounds after stiff-arming the Ravens' kicker.
Jacobs, a native of Richmond, spent most of last season on the practice squad, and his duties included serving as the opposing team's top wideout during scout-team drills.
"Tough break for Chuck," Harbaugh said. "He's been the type of guy where this is the first injury of his life. He can run all day. He's like the unbreakable man."