After the battle, Abbott remained in command of the regiment and was promoted to major on October 10, 1863. Four days later, the 20th Massachusetts Infantry fought in the small but sharp action at Bristoe Station, Virginia. Union forces were surprised by the attack of Confederate Lieutenant General A. P. Hill's men. The 20th Massachusetts Volunteer Infantry took few casualties, however, because they were able to fight from behind a steep railroad grade. After Major General Meade demonstrated against Confederate forces at the battle of Mine Run Creek, the Army of the Potomac went into winter quarters at Brandy Station, Virginia. In December 1863, Abbott received a 15-day leave to visit home, which was extended by 20 days due to his suffering from chronic diarrhea. In January 1864, Abbott left home to rejoin his regiment.