The 6-foot-2, 297-pound McDonald is entering his 10th NFL season and has played for Cincinnati, Seattle, Tampa Bay and Oakland. The 32-year-old played in 15 games with the Raiders last season, finishing with 31 tackles and two sacks.
The 6-foot-3, 282-pound Anau was with the Cardinals' practice squad in 2017 and also during the preseason last season. The Phoenix native played in college at Northern Arizona.
The Cardinals announced the signings Monday.