Mitchell made a pair of big-league appearances last year with the Marlins after spending the majority of the season at the Triple-A level between Miami and Philadelphia. The 30-year-old righty will function as organizational pitching depth this season.

Mitchell inked a minor-league deal with the Marlins in late July and wound up making a pair of relief appearance in late August before being designated for assignment. The 30-year-old righty spent the remainder of the year at Triple-A Jacksonville and has opted to search for a new home on the free agent market this offseason.

The 30-year-old right-hander was designated for assignment earlier in the week but passed through waivers unclaimed. He'll continue to provide minor league rotation depth for the Marlins.

Miami needed to create room after promoting top prospect Edward Cabrera on Wednesday and Mitchell was the odd man out. The 30-year-old carries a 5.13 ERA and 1.59 WHIP over 40 1/3 innings this season in the minor leagues.