Until proven otherwise on screen, I like to think that Worf was still the Federation Ambassador to the Klingon Empire and was only back in uniform for his brief trip to the E-E for the Troi's wedding. After the E-E returned to Earth for repairs, he departed back to Qo'nos to continue his career as a diplomat.
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)