The Patriots’ official list of rookie free agents should be announced in the coming days. Because those agreements can be fluid, and things can change quickly, we’ve avoided them unless they were independently confirmed.

One that we feel comfortable locking in is South Florida defensive tackle Cory Grissom.

A source confirmed that Grissom has agreed to a deal with New England, and if NFL draft guru Gil Brandt is on the mark, the signing is a coup for the Patriots. Brandt, writing on NFL.com, ranked Grissom as the top undrafted defensive tackle.

The 6-foot-1 3/8 and 306 pound Grissom was a three-year starter at South Florida from 2010-2012, appearing in 37 games. Injuries over his college career might have contributed to him going undrafted.

The Pro Football Weekly draft preview projected Grissom as a fifth- to sixth-round pick. ESPN’s Scouts Inc. rated him as the 16th defensive tackle (Insider content).

The Patriots have Vince Wilfork, Tommy Kelly, Kyle Love and Brandon Deaderick as their top returning interior linemen, while Armond Armstead of the Canadian Football League could be a factor.

Now Grissom joins the mix and his profile as a two-down run-stuffer seems to fit closest to Love’s.

EXTRA POINT: Maryland defensive lineman Joe Vellano will attend Patriots rookie minicamp, the Albany Times-Union reports. It is unclear if Vellano will be in attendance on a tryout basis, or if he has signed a contract.