New photos of The next episode of Walking Dead could reveal who found Negan on his return to the Sanctuary in episode 8×14.
Although thousands of fans suspect that Carl somehow faked his death or somehow be alive enough to be found along Negan's path, the passenger seems to be Gregory of Xander Berkeley. New photos of the next episode show Gregory standing outside the Shrine with Simon, Dwight and other saviors. When he was last seen on the AMC show, Gregory fled the hill after escaping from prison with saviors who did not want anything to do with him.
With Jared and his gang being discovered at an outpost near the sanctuary, Gregory must have strayed on his own journey, separate from that of Dwight and Simon, who escaped in their convoy. The photo after Episode 8×15 shows him standing with the rest of the group.