Not much context was added to this, but both backs can catch the ball and will more than likely be in a negative game script against the Baltimore Ravens. Gibson was already a starter/flex option, so this could put McKissic on the flex radar in PPR leagues.
WAS RB J.D. McKissic - Week 6 Fantasy Football Outlook
Week 6 at New York Giants
J.D. McKissic saw a team-high eight targets last week, finishing 6-46 as a receiver. This is now back-to-back weeks where McKissic has seen eight targets, making him relevant in in full PPR leagues. Still, McKissic isn't terribly productive with no scores on the season, and a limited role as a rusher (three carries his last two games combined). He's a low-end flex play in PPR formats for Week 6 against the Giants.