Halifax boss Chris Wilder moved for Roberts following Peter Atherton's retirement and Michael Taylor's move to Lancaster City.
The news will be a blow to Southport, who had hoped to sign Roberts after a successful loan spell last season.
Roberts, who has made a handful of first-team appearances for Crewe, also spent time at Chester last season only making one apperance for the Deva outfit.
Roberts who's contract expires next summer will look to impress Chris Wilder during his five month loan at the Shay.