OT Mike Adams (2nd), DT Alameda Ta'amu (4th), RB Chris Rainey (5th) and WR Toney Clemons (7th) signed earlier, leaving just OG David DeCastro (1st), LB Sean Spence (3rd) and OG Kelvin Beachum (7th) left unsigned.
Paulson, a multi-faceted TE/H-back, is seen as a potential contributor due to his blocking and receiving ability. He was an offensive team MVP at Oregon.
Frederick's 29 pass break-ups rank 6th all time at Texas A&M, and is the 2012 continuation of the Steelers' stockpiling of young pass defenders. They've taken at least one cornerback in their last four drafts.
With the rookie minicamp wrapping up this past weekend, the Steelers look ahead to Organized Team Activities (OTAs), which begin May 22, and run three consecutive weekends (22-24, 29-31 and June 4-7).