Grinding as-in a somewhat continuous noise rather than a bumping/knocking noise? If so that isn't something I'd normally associate with a strut, unless you mean it only happens with the motion of turning the wheel (left or right), not so much keeping the wheel in a turned position, which could be a failed strut mount.
However if the driver's side strut is moving around loose compared to passenger side, then you may indeed need a strut or strut mount anyway (assuming the nuts aren't just loose) and could go ahead and replace that, then see if the noise halts, but if it's the strut instead of just the mount, usually you'd want to replace both sides for balanced handling, or if the struts are old (several years or approaching 50K mi.), you might want to replace the struts too at the same time, even if it is just the mount.
Since you already replaced the wheel bearings, I'd sooner think it was brakes, front differential, or (less likely with "grinding" noise) CV axle.
