Mate, he was behind Snake and Tom when he signed the extension - less than six months before he was granted the release. That's the point you missed - that circumstance did not change between him signing the extension and him being granted the release.
What DID change was 14 players being told they could/should look elsewhere, and a couple of players (Taupau and Walker) becoming available earlier than expected. Taupau is not a bad signing; Walker was never, and will never be, an upgrade on Gutherson. On attitude, guts and defensive ability alone, Gutho craps all over him, without even looking at attacking talent/potential.
If you're looking for the guy who got his reputation, his premiership, and his rep honours off the pure luck of coming into an established side at its peak - look no further than D. Walker.