Buchanan, 24, was a seventh-round pick of the Patriots back in 2013. He wound up appearing in three games last year and recorded two tackles before he was placed on season-ending injured reserve in October.
It would not be surprising to see him catch on with another team ahead of training camp.
Dorsey, 24, is a former seventh-round pick of the Packers back in 2013 out of Maryland. He suffered an injury during his rookie season, which subsequently cost him the entire 2013 season.
New England signed him to a contract back in March, but it appeared as though his chances of making the 53-man roster were slim.
In 2014, Dorsey appeared in three games, recording two tackles on special teams and one catch for 4 yards before once again being placed on injured reserve.