Lewis, a 6-foot-1, 200-pound linebacker out of Miami Central (Fla). High, had been committed to Tennessee since April. He originally chose the Vols over Florida, LSU, Alabama, Texas A&M, Penn State and Nebraska, among other schools.
Lewis previously had committed to Florida in 2019 only to decommit from the Gators four months later.
The decommitment leaves Tennessee with seven ESPN 300 commitments, led now by defensive end Dylan Brooks, the No. 17-ranked recruit overall.
Lewis wasn't the only decommitment Monday.
Florida State lost ESPN 300 quarterback Luke Altmyer, who tweeted: "Due to unforeseen circumstances that have lead (sic) to a very difficult recruiting process, I have decided to decommit from Florida State."
Altmyer, the No. 116-ranked recruit and from Starkville, Mississippi, was the only quarterback commitment the Seminoles had in the 2021 class, and he leaves the program searching for another signal caller. Depth will be important, as Florida State did not sign a quarterback in the 2018 or '19 classes.
Seminoles head coach Mike Norvell was able to sign Chubba Purdy and Tate Rodemaker in 2020, and the team has Jordan Travis on the roster, but no quarterbacks in three of the past four classes is not great for the future roster.
Altmyer is heavily considering Ole Miss going forward.
Auburn also suffered a decommitment Monday when ESPN 300 running back Armoni Goodwin announced he was pulling his pledge from the Tigers. Goodwin is the No. 100-ranked recruit and from Trussville, Alabama; he is now considering Alabama, Auburn, Florida State, Georgia and LSU.
Also, ESPN 300 wide receiver Kyron Ware-Hudson flipped his commitment from Oregon to USC on Monday. Ware-Hudson is the No. 115-ranked recruit in the country and hails from Mater Dei High in Santa Ana, California.
Flipping the 6-foot, 195-pound receiver has been part of USC's efforts to "take back the west" and keep more in-state prospects home. The campaign has been working in the 2021 class, as USC has six ESPN 300 prospects from California and nine ESPN 300 commitments in total. Compare that to the 2020 class, in which the Trojans had only one ESPN 300 prospect sign in the class.
The early signing period begins Dec. 16.