so after analyzing the season 3 trailer again i noticed a man behind andrea with a white/tan unbuttoned shirt then i examined merle at the end with a tannish unbuttoned shirt. coincedence maybe

but then look at merle he is looking down at a person possibbly andrea after sneaking up behind her and knockig her down saying look at your old pal merle

so with these facts i am 96% sure that is merle behind andrea