The team says it released offensive lineman Erik Pears on Wednesday to make room for Alford. Alford was cut by the Giants on Saturday because of New York's depth on the defensive line.
Alford missed all of last season with a knee injury. He had 3½ sacks his first two years in New York and also had a key sack of Tom Brady in the final minute of the Giants' Super Bowl win over New England in February 2008.
Alford worked with Raiders defensive line coach Mike Waufle, who spent the past six seasons in New York.