Harris (concussion) wasn't spotted at Thursday's practice, Jim McBride of The Boston Globe reports.
Fellow running back Rhamondre Stevenson remained sidelined as well, with both players still in the NFL's concussion protocol. What Harris can do at Friday's practice will be pivotal with regard to his chances of suiting up Sunday against the Browns, but for now Brandon Bolden and J.J. Taylor profile as the Patriots' healthy backfield options.