Devine Ozigbo is a surprising late round player who can do more than just fill a role. However, James Williams is a specific role player back. Williams is a pass catching threat, and nearly had as many career catches as carries.
This worked to his benefit as he showed strong hands, shiftiness in open space and vision to cut upfield once he secured the pass. Check downs and quick routes to the flats and over the middle can free Williams to make big plays.
Williams has been compared to James White and does show similarly in his prospect profile. White was a bit bigger and better between the tackles, but Williams had similar passing game work and athletic testing.
While Williams is still undersized he can compliment Tarik Cohen and the Bears could use Mike Davis as their power back. Williams and Cohen could get small doses between the tackles, and the Bears could rotate backs similarly to the New England Patriots and their usage of James White.
If the undersized Williams falls to round six or later the Bears should be pouncing on the idea.