In August, it emerged that Bratt will reprise his role as Manny's father and Gloria's ex-husband Javier.
Lloyd has now told TV Guide that Javier's reappearance will have a big impact on Jay (Ed O'Neill).
"Jay is surprised to learn how possessive he's become of Manny, and he's almost jealous of Javier and his influence on Manny," he said.
"He always looked at Manny as a price he paid to get Gloria, but now he's finding himself the actual father to him and wanting to shape his life."
Leslie Mann and Kevin Hart recently signed up for guest roles in Modern Family, which airs on Wednesdays on ABC in the US and on Fridays on Sky1 in the UK.