After Chickamauga, the Union army retreated to Chattanooga, which the Confederates soon put under siege. Part of the Confederate defenses were on Missionary Ridge, a ridge east of the city. In mid-October, Rosecrans was removed from command and replaced by Major General George Thomas. On November 25, Thomas's men attacked the Confederate position on Missionary Ridge, driving the defenders from the position. Other Union assailants attacked Patrick R. Cleburne's men further to the north, although Cleburne's men fought a strong rear guard action. Barrett's battery fought at multiple different points on the Confederate line, including with Cleburne and at a different point in the Confederate right center. The battery was forced to abandon a caisson on the field after it suffered damage. Two days after the fighting on Missionary Ridge, Cleburne was again holding the Confederate rear guard, this time during the Battle of Ringgold Gap. Barrett's battery saw action at Ringgold Gap, with one section slowing the Union advance enough to receive praise from Cleburne.