The irony of the whole question about withstanding Jackson's flank attack is that Hooker's original planning conceived various offensive alternatives, which envisioned dealing a devastating blow to the ANV:
1. Get in the rear of the ANV and cutoff communications with Richmond along the line of the Richmond, Fredericksburg and Potomac RR and force the ANV to retreat.
2. Or envelop the ANV between Fredericksburg and the Wilderness and destroy that army in open terrain.
Once Hooker abandoned his offensive movement and withdrew corps back towards the Wilderness, the game was already lost, and the opportunity for a strong "offensive/defense" by Lee was presented, leading to the famous flank attack by Jackson. At that stage of the operation, with Hooker going on the defensive, responsibility for protecting his flanks was of supreme importance. Had the XI Corps taken steps to deploy its pickets, skirmishers, and artillery, and put the Corps on full alert, the flank attack would not have accomplished what it set out to do.