However, Garafolo says that this move does not mean his season is necessarily over, as he could be a candidate to return later on in the year.
By placing Mitchell on I.R., it will cost him at least the first eight games of the season.
Mitchell, 28, is a former third-round pick of the Texans back in 2010. He spent four years in Houston before signing a four-year, $19 million contract that included $8 million guaranteed with the Dolphins.
Mitchell stands to make a base salary of $3.975 million for the 2016 season.
Last year, Mitchell appeared in 12 games for the Dolphins and recorded 22 tackles and no sacks.