The Cardinals quickly scooped up Dan Williams at pick 26, getting a big body (6-3, 327) who should help upgrade a run defense that last season allowed 4.5 yards per carry and 112.8 yards per game - ranking 17th among the 32 NFL teams in the latter category.
Robinson is a 35-year-old veteran of 14 pro seasons. The 6-4, 305-pounder started for the Cards in 2008 and 2009 - recording 17 solos and 11 assists in the latter - but has not been signed to a contract for 2010. He is currently a free agent.
Watson, a five-year veteran, packs 329 pounds on a 6-4 frame. He contributed 22 solos and 6 assists as Robinson's chief backup last season.
Alan Branch, a four-year veteran, has the size to play the nose (6-5, 338) but is listed as a tackle. He recorded 14 solos and 4 assists in 2009.
The only other interior line candidate on the Cardinals' current roster is 6-3, 305-pound Keilen Dykes, a two-year veteran who registered just 1 tackle last season.
Williams is somewhat limited as a pass rusher but that apparently is not a big concern for Arizona. The Cardinals registered 43 sacks last season, despite getting just one from Robinson and none from Watson.