The Patriots are now just one player away from having their entire rookie class under contract before the end of the offseason program. Second-round receiver Aaron Dobson is the lone holdout, and his contract is likely to be completed soon.
Buchanan started 32 games at Illinois and had 11.5 sacks over the past two seasons, including a team-high 4.5 in 2012. He will compete with Jermaine Cunningham, Justin Francis, Jake Bequette, Marcus Benard, and Jason Vega for the backup pass-rusher spots.
The Patriots held the first of three days of OTA practice Tuesday, and Wednesday's session will be open to the media.