The exec said that Stonestreet, who plays gay dad Cameron Tucker in Modern Family, should make an appearance if there are no filming clashes between the two shows.
"We are still looking for something for Eric Stonestreet to play, because he's a Kansas boy, and he'd like to play a bad guy," Yost told TV Guide.
"So if we can come up with something that fits in with [their] schedule, of course we will... he's just great."
Yost recently admitted that he has been trying to get Stonestreet on Justified "since the end of the first season".
The actor made a guest appearance in fellow FX series American Horror Story last year.
Justified's third season concluded in the US last night (April 10). It currently airs in the UK on Wednesdays at 9pm on 5USA.