The Patriots also waived DT Isaiah Mack.
Calhoun, 28, is a former third-round pick of the Raiders back in 2016. He was in the second year of his four-year, $3.29 million contract and set to make a base salary of $565,000 when the Raiders cut him loose coming out of the preseason in 2017.
The Raiders later signed him to their practice squad and brought him back on an exclusive rights deal in 2018. He later signed on with the Patriots after the draft last year and returned to New England this past March.
In 2020, Calhoun has appeared in eight games for the Patriots and recorded 14 tackles, two sacks and two forced fumbles.