At the time of the late December battle at Chickasaw Bayou, the 7th Texas [Gregg's own regiment] was not a part of Gregg's Brigade. It was then on duty in Port Hudson as a small part of a consolidated regiment that also included two Tennessee regiments.

A few days after the engagements at Chickasaw Bayou, Gregg’s brigade was detached from the Vicksburg command and sent to Port Hudson.

The effective strength of Gregg's regiments on January 3, 1863 was reported as:
10Tn-349
50/51/1Tn Bn-512
3/30 Tn-851
41Tn-526

Soon after Gen Gregg's brigade arrived, Gen Gardner commanding at Port Hudson, rearranged the brigade organizations at Port Hudson. This is when the 9th La Battalion was added to Gregg’s Brigade.

Later in January, the 7th Texas received enough recruits, absentees, etc., etc., to resume its separate identity apart from the consolidated regiment. The 7th Texas was then added to Gregg’s Brigade

In common with several other depleted units, including the Tennessee regiments of Gregg's brigade, the 7th Texas had been released from prison camps in September 1862. Due to their diminished strength, many such regiments had then been reorganized into various consolidations.