Ellison, a third-round pick by Carolina in 2005, was waived for the fifth time in his three-year NFL career Saturday when the Ravens made their final cuts. Though the 49ers are his fourth NFL team, Ellison still hasn't played in a regular-season game.

If Ellison sticks with San Francisco, he'll provide depth on the 49ers' line while playing behind nose tackle Aubrayo Franklin, his teammate in Baltimore last season. San Francisco's defensive line is fairly thin after losing recent draft picks Melvin Oliver and Joe Cohen to season-ending injuries.

The former Missouri star spent time on the Panthers' practice squad and the active roster in 2005, but was claimed by Houston after Carolina cut him last September. The Texans waived him four days later, and he spent most of last season on Baltimore's practice squad before joining the active roster for three games in December.

Ellison was second on the Ravens' depth chart behind nose tackle Kelly Gregg during training camp, but still got released.