Although Allen has committed to voice Buzz again, it doesn't necessarily mean that Pixar has given a green light to another feature-length sequel of the franchise.
It seems that Disney and Pixar are still reluctant to end "Toy Story" with the third film. Despite speculation that the hit animated film series will meet its final chapter in "Toy Story 3", it has been reported that Tim Allen has signed on for "Toy Story 4".
According to The Wrap which claims to have learned the matter from individuals familiar with the "The Six Wives of Henry Lefay" star's contract, Allen is under contract to reprise his role as Buzz Lightyear. However, his commitment "does not necessarily mean that Pixar has plans to put another feature-length sequel into production."
Still, this could give a hope that Disney and Pixar are considering about the possibility to extend the franchise. The Wrap additionally states Allen's commitment for "Toy Story 4" can suggest that he and other stars have also signed for "multiple films some time ago".
Previously, Disney and Pixar have already announced that the "Toy Story" characters will appear in a short film in front of "Cars 2", which opens in 2011. However, a Disney spokesperson told The Wrap in an old interview that they had "nothing to announce regarding another full-length feature."
Similar to the statement released by the spokesperson, "Toy Story 3" director Lee Unkrich has stated, "That being said, we know that people love the characters, love Woody and Buzz, and would hate to say good-bye to them completely. ... We don't have any plans for (a fourth movie) - but we are trying to find ways to keep the characters alive."