Today, Cartoon Network released information about their programming lineup for the 2013-2014 season. While the network did announce three animated shorts called The Yoda Chronicles, there is no mention of Star Wars: The Clone Wars anywhere in the press release. It's possible that this is the first concrete indication that The Clone Wars will move to Disney's airwaves after Season 5 concludes in the spring.
Cartoon Network's omission of one of its highest-performing animated series led to renewed discussion about the show possibly moving from the network to rival kids' channel Disney XD. Even before Disney's $4 billion purchase of Lucasfilm had closed, fans were speculating that such a change was inevitable. How long would Disney allow its intellectual property to generate revenue for Cartoon Network, a subsidiary of Time Warner's Turner Broadcasting System, when it owned a channel that competed with Cartoon Network? Such a move would certainly increase the consolidation of Star Wars content under the Disney umbrella. (That centralization is likely to continue in a few years: Disney is widely expected to acquire the theatrical, nontheatrical, and home video distribution rights for the first six films from 20th Century Fox.)
There are other possibilities. The "returning series/specials" list, where The Clone Wars would have appeared, excludes most of Cartoon Network's Saturday morning shows (not just TCW) and consists mostly of its primetime programming. However, the list does include Beyblade: Metal Fury, which currently airs on Saturdays like The Clone Wars.
Another explanation is that The Clone Wars will end after Season 5, although given how much work has gone into Season 6, that seems unlikely.