Gragas, one of the most played champions in the League of Legend World Championships so far, has been removed from competitive play. The decision was taken by Riot after Fnatic's match vs Edward Gaming, in which a bug was discovered 20 minutes in which prevented the champion from casting one of his abilities.
In the case of that series, both teams agreed to a remake in which Fnatic picked up Gragas again with no problems—as did Edward Gaming in match three. While Riot stated at the time that they would leave the champion in play unless the bug appeared again, they've since changed their minds upon learning that it's much more likely to crop up than they originally thought.
"We don't want to endanger the integrity of the upcoming games or risk additional remakes, so we are disabling Gragas for the remainder of the tournament" said Riot in a statement. "The bug is also reproducible on Lux and Ziggs, and so to be safe, we are disabling them for the remainder of the trounament.
The other two champions haven't been picked at all so far, but Gragas has appeared in 29 of the 38 games so far, and it's hard to see how the removal of such a popular hero won't have a big impact on the meta. There's been some suggestion that the change might have more of an impact on European teams, given how much more often he's picked up by them.
It'll be interesting to see how the rest of the tournament plays out.