The Rock isn't saying that he's in talks to play Green Lantern John Stewart in live action, but he's not saying he isn't either.
After a picture on Instagram with his old friend Hiram Garcia (now a producer) included the hashtag #JohnStewartCanStillWhupSupermansAss, a couple of sites picked up on the hashtag and started the speculation engines. While Dwayne Johnson retweeted IGN's story on the hashtag (I know, I can hardly believe the things I'm writing here either), he did also say "All I said was.. #LanternCanWhupSuperman."
So, it doesn't sound like he's really teasing much. In fact, using easy context clues, since he had the initial hashtag in a picture with a friend of his since he was 15, it's probably just an old argument between Johnson and Garcia.
Now, back on the last day of 2013, Johnson did tweet that he had a talk with Warner Bros so John Stewart isn't outside the realm of possibility. Either way, it's clear that at least fans would really like to see Dwayne "The Rock" Johnson in a DC hero role. Changing Green Lanterns for the big screen would probably be a good move, judging by how Hal Jordan's first go… went.