Executive producers Marc Guggenheim and Andrew Kreisberg have both mentioned a desire to see the Smallville star cameo in their new television series.
Hartley played Green Arrow - the hero on which the new show is based - in The CW's series, which concluded last year.
"We have some funny ideas for how to [include Hartley]," Kreisberg told Green Arrow TV. "More than anything, Justin has been so amazing and so supportive of this.
"Neither of us really knew him before we worked on this pilot. We actually met him during pilot season, and he's just been so cool... and he and [Arrow star Stephen Amell] have actually developed a nice friendship.
"So, we hope, in the same way that in the Superman movies you would see actors from previous incarnations joined in some way... if there's an opportunity down the road for Justin to play with us, that would be great."
"I really want to have Justin Hartley on the show in a cameo, and everyone will hopefully laugh and we come up with a clever enough cameo," Guggenheim told IGN.
Guggenheim recently explained why Hartley had not been cast in the starring role in Arrow.